xref: /vim-8.2.3635/src/window.c (revision 6ef8f9ea)
1 /* vi:set ts=8 sts=4 sw=4 noet:
2  *
3  * VIM - Vi IMproved	by Bram Moolenaar
4  *
5  * Do ":help uganda"  in Vim to read a list of people who contributed.
6  * Do ":help credits" in Vim to see a list of people who contributed.
7  * See README.txt for an overview of the Vim source code.
8  */
9 
10 #include "vim.h"
11 
12 static void cmd_with_count(char *cmd, char_u *bufp, size_t bufsize, long Prenum);
13 static void win_init(win_T *newp, win_T *oldp, int flags);
14 static void win_init_some(win_T *newp, win_T *oldp);
15 static void frame_comp_pos(frame_T *topfrp, int *row, int *col);
16 static void frame_setheight(frame_T *curfrp, int height);
17 static void frame_setwidth(frame_T *curfrp, int width);
18 static void win_exchange(long);
19 static void win_rotate(int, int);
20 static void win_totop(int size, int flags);
21 static void win_equal_rec(win_T *next_curwin, int current, frame_T *topfr, int dir, int col, int row, int width, int height);
22 static win_T *win_free_mem(win_T *win, int *dirp, tabpage_T *tp);
23 static frame_T *win_altframe(win_T *win, tabpage_T *tp);
24 static tabpage_T *alt_tabpage(void);
25 static win_T *frame2win(frame_T *frp);
26 static int frame_has_win(frame_T *frp, win_T *wp);
27 static void frame_new_height(frame_T *topfrp, int height, int topfirst, int wfh);
28 static int frame_fixed_height(frame_T *frp);
29 static int frame_fixed_width(frame_T *frp);
30 static void frame_add_statusline(frame_T *frp);
31 static void frame_new_width(frame_T *topfrp, int width, int leftfirst, int wfw);
32 static void frame_add_vsep(frame_T *frp);
33 static int frame_minwidth(frame_T *topfrp, win_T *next_curwin);
34 static void frame_fix_width(win_T *wp);
35 static int win_alloc_firstwin(win_T *oldwin);
36 static void new_frame(win_T *wp);
37 static tabpage_T *alloc_tabpage(void);
38 static int leave_tabpage(buf_T *new_curbuf, int trigger_leave_autocmds);
39 static void enter_tabpage(tabpage_T *tp, buf_T *old_curbuf, int trigger_enter_autocmds, int trigger_leave_autocmds);
40 static void frame_fix_height(win_T *wp);
41 static int frame_minheight(frame_T *topfrp, win_T *next_curwin);
42 static void win_enter_ext(win_T *wp, int undo_sync, int no_curwin, int trigger_new_autocmds, int trigger_enter_autocmds, int trigger_leave_autocmds);
43 static void win_free(win_T *wp, tabpage_T *tp);
44 static void frame_append(frame_T *after, frame_T *frp);
45 static void frame_insert(frame_T *before, frame_T *frp);
46 static void frame_remove(frame_T *frp);
47 static void win_goto_ver(int up, long count);
48 static void win_goto_hor(int left, long count);
49 static void frame_add_height(frame_T *frp, int n);
50 static void last_status_rec(frame_T *fr, int statusline);
51 
52 static void make_snapshot_rec(frame_T *fr, frame_T **frp);
53 static void clear_snapshot(tabpage_T *tp, int idx);
54 static void clear_snapshot_rec(frame_T *fr);
55 static int check_snapshot_rec(frame_T *sn, frame_T *fr);
56 static win_T *restore_snapshot_rec(frame_T *sn, frame_T *fr);
57 
58 static int frame_check_height(frame_T *topfrp, int height);
59 static int frame_check_width(frame_T *topfrp, int width);
60 
61 static win_T *win_alloc(win_T *after, int hidden);
62 
63 #define NOWIN		(win_T *)-1	/* non-existing window */
64 
65 #define ROWS_AVAIL (Rows - p_ch - tabline_height())
66 
67 static char *m_onlyone = N_("Already only one window");
68 
69 /*
70  * All CTRL-W window commands are handled here, called from normal_cmd().
71  */
72     void
73 do_window(
74     int		nchar,
75     long	Prenum,
76     int		xchar)	    /* extra char from ":wincmd gx" or NUL */
77 {
78     long	Prenum1;
79     win_T	*wp;
80 #if defined(FEAT_SEARCHPATH) || defined(FEAT_FIND_ID)
81     char_u	*ptr;
82     linenr_T    lnum = -1;
83 #endif
84 #ifdef FEAT_FIND_ID
85     int		type = FIND_DEFINE;
86     int		len;
87 #endif
88     char_u	cbuf[40];
89 
90     Prenum1 = Prenum == 0 ? 1 : Prenum;
91 
92 #ifdef FEAT_CMDWIN
93 # define CHECK_CMDWIN \
94     do { \
95 	if (cmdwin_type != 0) \
96 	{ \
97 	    emsg(_(e_cmdwin)); \
98 	    return; \
99 	} \
100     } while (0)
101 #else
102 # define CHECK_CMDWIN do { /**/ } while (0)
103 #endif
104 
105     switch (nchar)
106     {
107 /* split current window in two parts, horizontally */
108     case 'S':
109     case Ctrl_S:
110     case 's':
111 		CHECK_CMDWIN;
112 		reset_VIsual_and_resel();	/* stop Visual mode */
113 #ifdef FEAT_QUICKFIX
114 		/* When splitting the quickfix window open a new buffer in it,
115 		 * don't replicate the quickfix buffer. */
116 		if (bt_quickfix(curbuf))
117 		    goto newwindow;
118 #endif
119 #ifdef FEAT_GUI
120 		need_mouse_correct = TRUE;
121 #endif
122 		(void)win_split((int)Prenum, 0);
123 		break;
124 
125 /* split current window in two parts, vertically */
126     case Ctrl_V:
127     case 'v':
128 		CHECK_CMDWIN;
129 		reset_VIsual_and_resel();	/* stop Visual mode */
130 #ifdef FEAT_QUICKFIX
131 		/* When splitting the quickfix window open a new buffer in it,
132 		 * don't replicate the quickfix buffer. */
133 		if (bt_quickfix(curbuf))
134 		    goto newwindow;
135 #endif
136 #ifdef FEAT_GUI
137 		need_mouse_correct = TRUE;
138 #endif
139 		(void)win_split((int)Prenum, WSP_VERT);
140 		break;
141 
142 /* split current window and edit alternate file */
143     case Ctrl_HAT:
144     case '^':
145 		CHECK_CMDWIN;
146 		reset_VIsual_and_resel();	/* stop Visual mode */
147 
148 		if (buflist_findnr(Prenum == 0
149 					? curwin->w_alt_fnum : Prenum) == NULL)
150 		{
151 		    if (Prenum == 0)
152 			emsg(_(e_noalt));
153 		    else
154 			semsg(_("E92: Buffer %ld not found"), Prenum);
155 		    break;
156 		}
157 
158 		if (!curbuf_locked() && win_split(0, 0) == OK)
159 		    (void)buflist_getfile(
160 			    Prenum == 0 ? curwin->w_alt_fnum : Prenum,
161 			    (linenr_T)0, GETF_ALT, FALSE);
162 		break;
163 
164 /* open new window */
165     case Ctrl_N:
166     case 'n':
167 		CHECK_CMDWIN;
168 		reset_VIsual_and_resel();	/* stop Visual mode */
169 #ifdef FEAT_QUICKFIX
170 newwindow:
171 #endif
172 		if (Prenum)
173 		    /* window height */
174 		    vim_snprintf((char *)cbuf, sizeof(cbuf) - 5, "%ld", Prenum);
175 		else
176 		    cbuf[0] = NUL;
177 #if defined(FEAT_QUICKFIX)
178 		if (nchar == 'v' || nchar == Ctrl_V)
179 		    STRCAT(cbuf, "v");
180 #endif
181 		STRCAT(cbuf, "new");
182 		do_cmdline_cmd(cbuf);
183 		break;
184 
185 /* quit current window */
186     case Ctrl_Q:
187     case 'q':
188 		reset_VIsual_and_resel();	/* stop Visual mode */
189 		cmd_with_count("quit", cbuf, sizeof(cbuf), Prenum);
190 		do_cmdline_cmd(cbuf);
191 		break;
192 
193 /* close current window */
194     case Ctrl_C:
195     case 'c':
196 		reset_VIsual_and_resel();	/* stop Visual mode */
197 		cmd_with_count("close", cbuf, sizeof(cbuf), Prenum);
198 		do_cmdline_cmd(cbuf);
199 		break;
200 
201 #if defined(FEAT_QUICKFIX)
202 /* close preview window */
203     case Ctrl_Z:
204     case 'z':
205 		CHECK_CMDWIN;
206 		reset_VIsual_and_resel();	/* stop Visual mode */
207 		do_cmdline_cmd((char_u *)"pclose");
208 		break;
209 
210 /* cursor to preview window */
211     case 'P':
212 		FOR_ALL_WINDOWS(wp)
213 		    if (wp->w_p_pvw)
214 			break;
215 		if (wp == NULL)
216 		    emsg(_("E441: There is no preview window"));
217 		else
218 		    win_goto(wp);
219 		break;
220 #endif
221 
222 /* close all but current window */
223     case Ctrl_O:
224     case 'o':
225 		CHECK_CMDWIN;
226 		reset_VIsual_and_resel();	/* stop Visual mode */
227 		cmd_with_count("only", cbuf, sizeof(cbuf), Prenum);
228 		do_cmdline_cmd(cbuf);
229 		break;
230 
231 /* cursor to next window with wrap around */
232     case Ctrl_W:
233     case 'w':
234 /* cursor to previous window with wrap around */
235     case 'W':
236 		CHECK_CMDWIN;
237 		if (ONE_WINDOW && Prenum != 1)	/* just one window */
238 		    beep_flush();
239 		else
240 		{
241 		    if (Prenum)			/* go to specified window */
242 		    {
243 			for (wp = firstwin; --Prenum > 0; )
244 			{
245 			    if (wp->w_next == NULL)
246 				break;
247 			    else
248 				wp = wp->w_next;
249 			}
250 		    }
251 		    else
252 		    {
253 			if (nchar == 'W')	    /* go to previous window */
254 			{
255 			    wp = curwin->w_prev;
256 			    if (wp == NULL)
257 				wp = lastwin;	    /* wrap around */
258 			}
259 			else			    /* go to next window */
260 			{
261 			    wp = curwin->w_next;
262 			    if (wp == NULL)
263 				wp = firstwin;	    /* wrap around */
264 			}
265 		    }
266 		    win_goto(wp);
267 		}
268 		break;
269 
270 /* cursor to window below */
271     case 'j':
272     case K_DOWN:
273     case Ctrl_J:
274 		CHECK_CMDWIN;
275 		win_goto_ver(FALSE, Prenum1);
276 		break;
277 
278 /* cursor to window above */
279     case 'k':
280     case K_UP:
281     case Ctrl_K:
282 		CHECK_CMDWIN;
283 		win_goto_ver(TRUE, Prenum1);
284 		break;
285 
286 /* cursor to left window */
287     case 'h':
288     case K_LEFT:
289     case Ctrl_H:
290     case K_BS:
291 		CHECK_CMDWIN;
292 		win_goto_hor(TRUE, Prenum1);
293 		break;
294 
295 /* cursor to right window */
296     case 'l':
297     case K_RIGHT:
298     case Ctrl_L:
299 		CHECK_CMDWIN;
300 		win_goto_hor(FALSE, Prenum1);
301 		break;
302 
303 /* move window to new tab page */
304     case 'T':
305 		if (one_window())
306 		    msg(_(m_onlyone));
307 		else
308 		{
309 		    tabpage_T	*oldtab = curtab;
310 		    tabpage_T	*newtab;
311 
312 		    /* First create a new tab with the window, then go back to
313 		     * the old tab and close the window there. */
314 		    wp = curwin;
315 		    if (win_new_tabpage((int)Prenum) == OK
316 						     && valid_tabpage(oldtab))
317 		    {
318 			newtab = curtab;
319 			goto_tabpage_tp(oldtab, TRUE, TRUE);
320 			if (curwin == wp)
321 			    win_close(curwin, FALSE);
322 			if (valid_tabpage(newtab))
323 			    goto_tabpage_tp(newtab, TRUE, TRUE);
324 		    }
325 		}
326 		break;
327 
328 /* cursor to top-left window */
329     case 't':
330     case Ctrl_T:
331 		win_goto(firstwin);
332 		break;
333 
334 /* cursor to bottom-right window */
335     case 'b':
336     case Ctrl_B:
337 		win_goto(lastwin);
338 		break;
339 
340 /* cursor to last accessed (previous) window */
341     case 'p':
342     case Ctrl_P:
343 		if (!win_valid(prevwin))
344 		    beep_flush();
345 		else
346 		    win_goto(prevwin);
347 		break;
348 
349 /* exchange current and next window */
350     case 'x':
351     case Ctrl_X:
352 		CHECK_CMDWIN;
353 		win_exchange(Prenum);
354 		break;
355 
356 /* rotate windows downwards */
357     case Ctrl_R:
358     case 'r':
359 		CHECK_CMDWIN;
360 		reset_VIsual_and_resel();	/* stop Visual mode */
361 		win_rotate(FALSE, (int)Prenum1);    /* downwards */
362 		break;
363 
364 /* rotate windows upwards */
365     case 'R':
366 		CHECK_CMDWIN;
367 		reset_VIsual_and_resel();	/* stop Visual mode */
368 		win_rotate(TRUE, (int)Prenum1);	    /* upwards */
369 		break;
370 
371 /* move window to the very top/bottom/left/right */
372     case 'K':
373     case 'J':
374     case 'H':
375     case 'L':
376 		CHECK_CMDWIN;
377 		win_totop((int)Prenum,
378 			((nchar == 'H' || nchar == 'L') ? WSP_VERT : 0)
379 			| ((nchar == 'H' || nchar == 'K') ? WSP_TOP : WSP_BOT));
380 		break;
381 
382 /* make all windows the same height */
383     case '=':
384 #ifdef FEAT_GUI
385 		need_mouse_correct = TRUE;
386 #endif
387 		win_equal(NULL, FALSE, 'b');
388 		break;
389 
390 /* increase current window height */
391     case '+':
392 #ifdef FEAT_GUI
393 		need_mouse_correct = TRUE;
394 #endif
395 		win_setheight(curwin->w_height + (int)Prenum1);
396 		break;
397 
398 /* decrease current window height */
399     case '-':
400 #ifdef FEAT_GUI
401 		need_mouse_correct = TRUE;
402 #endif
403 		win_setheight(curwin->w_height - (int)Prenum1);
404 		break;
405 
406 /* set current window height */
407     case Ctrl__:
408     case '_':
409 #ifdef FEAT_GUI
410 		need_mouse_correct = TRUE;
411 #endif
412 		win_setheight(Prenum ? (int)Prenum : 9999);
413 		break;
414 
415 /* increase current window width */
416     case '>':
417 #ifdef FEAT_GUI
418 		need_mouse_correct = TRUE;
419 #endif
420 		win_setwidth(curwin->w_width + (int)Prenum1);
421 		break;
422 
423 /* decrease current window width */
424     case '<':
425 #ifdef FEAT_GUI
426 		need_mouse_correct = TRUE;
427 #endif
428 		win_setwidth(curwin->w_width - (int)Prenum1);
429 		break;
430 
431 /* set current window width */
432     case '|':
433 #ifdef FEAT_GUI
434 		need_mouse_correct = TRUE;
435 #endif
436 		win_setwidth(Prenum != 0 ? (int)Prenum : 9999);
437 		break;
438 
439 /* jump to tag and split window if tag exists (in preview window) */
440 #if defined(FEAT_QUICKFIX)
441     case '}':
442 		CHECK_CMDWIN;
443 		if (Prenum)
444 		    g_do_tagpreview = Prenum;
445 		else
446 		    g_do_tagpreview = p_pvh;
447 #endif
448 		/* FALLTHROUGH */
449     case ']':
450     case Ctrl_RSB:
451 		CHECK_CMDWIN;
452 		/* keep Visual mode, can select words to use as a tag */
453 		if (Prenum)
454 		    postponed_split = Prenum;
455 		else
456 		    postponed_split = -1;
457 #ifdef FEAT_QUICKFIX
458 		if (nchar != '}')
459 		    g_do_tagpreview = 0;
460 #endif
461 
462 		/* Execute the command right here, required when "wincmd ]"
463 		 * was used in a function. */
464 		do_nv_ident(Ctrl_RSB, NUL);
465 		break;
466 
467 #ifdef FEAT_SEARCHPATH
468 /* edit file name under cursor in a new window */
469     case 'f':
470     case 'F':
471     case Ctrl_F:
472 wingotofile:
473 		CHECK_CMDWIN;
474 
475 		ptr = grab_file_name(Prenum1, &lnum);
476 		if (ptr != NULL)
477 		{
478 		    tabpage_T	*oldtab = curtab;
479 		    win_T	*oldwin = curwin;
480 # ifdef FEAT_GUI
481 		    need_mouse_correct = TRUE;
482 # endif
483 		    setpcmark();
484 		    if (win_split(0, 0) == OK)
485 		    {
486 			RESET_BINDING(curwin);
487 			if (do_ecmd(0, ptr, NULL, NULL, ECMD_LASTL,
488 						   ECMD_HIDE, NULL) == FAIL)
489 			{
490 			    /* Failed to open the file, close the window
491 			     * opened for it. */
492 			    win_close(curwin, FALSE);
493 			    goto_tabpage_win(oldtab, oldwin);
494 			}
495 			else if (nchar == 'F' && lnum >= 0)
496 			{
497 			    curwin->w_cursor.lnum = lnum;
498 			    check_cursor_lnum();
499 			    beginline(BL_SOL | BL_FIX);
500 			}
501 		    }
502 		    vim_free(ptr);
503 		}
504 		break;
505 #endif
506 
507 #ifdef FEAT_FIND_ID
508 /* Go to the first occurrence of the identifier under cursor along path in a
509  * new window -- webb
510  */
511     case 'i':			    /* Go to any match */
512     case Ctrl_I:
513 		type = FIND_ANY;
514 		/* FALLTHROUGH */
515     case 'd':			    /* Go to definition, using 'define' */
516     case Ctrl_D:
517 		CHECK_CMDWIN;
518 		if ((len = find_ident_under_cursor(&ptr, FIND_IDENT)) == 0)
519 		    break;
520 		find_pattern_in_path(ptr, 0, len, TRUE,
521 			Prenum == 0 ? TRUE : FALSE, type,
522 			Prenum1, ACTION_SPLIT, (linenr_T)1, (linenr_T)MAXLNUM);
523 		curwin->w_set_curswant = TRUE;
524 		break;
525 #endif
526 
527 /* Quickfix window only: view the result under the cursor in a new split. */
528 #if defined(FEAT_QUICKFIX)
529     case K_KENTER:
530     case CAR:
531 		if (bt_quickfix(curbuf))
532 		    qf_view_result(TRUE);
533 		break;
534 #endif
535 
536 /* CTRL-W g  extended commands */
537     case 'g':
538     case Ctrl_G:
539 		CHECK_CMDWIN;
540 #ifdef USE_ON_FLY_SCROLL
541 		dont_scroll = TRUE;		/* disallow scrolling here */
542 #endif
543 		++no_mapping;
544 		++allow_keys;   /* no mapping for xchar, but allow key codes */
545 		if (xchar == NUL)
546 		    xchar = plain_vgetc();
547 		LANGMAP_ADJUST(xchar, TRUE);
548 		--no_mapping;
549 		--allow_keys;
550 #ifdef FEAT_CMDL_INFO
551 		(void)add_to_showcmd(xchar);
552 #endif
553 		switch (xchar)
554 		{
555 #if defined(FEAT_QUICKFIX)
556 		    case '}':
557 			xchar = Ctrl_RSB;
558 			if (Prenum)
559 			    g_do_tagpreview = Prenum;
560 			else
561 			    g_do_tagpreview = p_pvh;
562 #endif
563 			/* FALLTHROUGH */
564 		    case ']':
565 		    case Ctrl_RSB:
566 			/* keep Visual mode, can select words to use as a tag */
567 			if (Prenum)
568 			    postponed_split = Prenum;
569 			else
570 			    postponed_split = -1;
571 
572 			/* Execute the command right here, required when
573 			 * "wincmd g}" was used in a function. */
574 			do_nv_ident('g', xchar);
575 			break;
576 
577 #ifdef FEAT_SEARCHPATH
578 		    case 'f':	    /* CTRL-W gf: "gf" in a new tab page */
579 		    case 'F':	    /* CTRL-W gF: "gF" in a new tab page */
580 			cmdmod.tab = tabpage_index(curtab) + 1;
581 			nchar = xchar;
582 			goto wingotofile;
583 #endif
584 		    case 't':	    // CTRL-W gt: go to next tab page
585 			goto_tabpage((int)Prenum);
586 			break;
587 
588 		    case 'T':	    // CTRL-W gT: go to previous tab page
589 			goto_tabpage(-(int)Prenum1);
590 			break;
591 
592 		    default:
593 			beep_flush();
594 			break;
595 		}
596 		break;
597 
598     default:	beep_flush();
599 		break;
600     }
601 }
602 
603 /*
604  * Figure out the address type for ":wnncmd".
605  */
606     void
607 get_wincmd_addr_type(char_u *arg, exarg_T *eap)
608 {
609     switch (*arg)
610     {
611     case 'S':
612     case Ctrl_S:
613     case 's':
614     case Ctrl_N:
615     case 'n':
616     case 'j':
617     case Ctrl_J:
618     case 'k':
619     case Ctrl_K:
620     case 'T':
621     case Ctrl_R:
622     case 'r':
623     case 'R':
624     case 'K':
625     case 'J':
626     case '+':
627     case '-':
628     case Ctrl__:
629     case '_':
630     case '|':
631     case ']':
632     case Ctrl_RSB:
633     case 'g':
634     case Ctrl_G:
635     case Ctrl_V:
636     case 'v':
637     case 'h':
638     case Ctrl_H:
639     case 'l':
640     case Ctrl_L:
641     case 'H':
642     case 'L':
643     case '>':
644     case '<':
645 #if defined(FEAT_QUICKFIX)
646     case '}':
647 #endif
648 #ifdef FEAT_SEARCHPATH
649     case 'f':
650     case 'F':
651     case Ctrl_F:
652 #endif
653 #ifdef FEAT_FIND_ID
654     case 'i':
655     case Ctrl_I:
656     case 'd':
657     case Ctrl_D:
658 #endif
659 		/* window size or any count */
660 		eap->addr_type = ADDR_LINES;
661 		break;
662 
663     case Ctrl_HAT:
664     case '^':
665 		/* buffer number */
666 		eap->addr_type = ADDR_BUFFERS;
667 		break;
668 
669     case Ctrl_Q:
670     case 'q':
671     case Ctrl_C:
672     case 'c':
673     case Ctrl_O:
674     case 'o':
675     case Ctrl_W:
676     case 'w':
677     case 'W':
678     case 'x':
679     case Ctrl_X:
680 		/* window number */
681 		eap->addr_type = ADDR_WINDOWS;
682 		break;
683 
684 #if defined(FEAT_QUICKFIX)
685     case Ctrl_Z:
686     case 'z':
687     case 'P':
688 #endif
689     case 't':
690     case Ctrl_T:
691     case 'b':
692     case Ctrl_B:
693     case 'p':
694     case Ctrl_P:
695     case '=':
696     case CAR:
697 		/* no count */
698 		eap->addr_type = 0;
699 		break;
700     }
701 }
702 
703     static void
704 cmd_with_count(
705     char	*cmd,
706     char_u	*bufp,
707     size_t	bufsize,
708     long	Prenum)
709 {
710     size_t	len = STRLEN(cmd);
711 
712     STRCPY(bufp, cmd);
713     if (Prenum > 0)
714 	vim_snprintf((char *)bufp + len, bufsize - len, "%ld", Prenum);
715 }
716 
717 /*
718  * split the current window, implements CTRL-W s and :split
719  *
720  * "size" is the height or width for the new window, 0 to use half of current
721  * height or width.
722  *
723  * "flags":
724  * WSP_ROOM: require enough room for new window
725  * WSP_VERT: vertical split.
726  * WSP_TOP:  open window at the top-left of the shell (help window).
727  * WSP_BOT:  open window at the bottom-right of the shell (quickfix window).
728  * WSP_HELP: creating the help window, keep layout snapshot
729  *
730  * return FAIL for failure, OK otherwise
731  */
732     int
733 win_split(int size, int flags)
734 {
735     /* When the ":tab" modifier was used open a new tab page instead. */
736     if (may_open_tabpage() == OK)
737 	return OK;
738 
739     /* Add flags from ":vertical", ":topleft" and ":botright". */
740     flags |= cmdmod.split;
741     if ((flags & WSP_TOP) && (flags & WSP_BOT))
742     {
743 	emsg(_("E442: Can't split topleft and botright at the same time"));
744 	return FAIL;
745     }
746 
747     /* When creating the help window make a snapshot of the window layout.
748      * Otherwise clear the snapshot, it's now invalid. */
749     if (flags & WSP_HELP)
750 	make_snapshot(SNAP_HELP_IDX);
751     else
752 	clear_snapshot(curtab, SNAP_HELP_IDX);
753 
754     return win_split_ins(size, flags, NULL, 0);
755 }
756 
757 /*
758  * When "new_wp" is NULL: split the current window in two.
759  * When "new_wp" is not NULL: insert this window at the far
760  * top/left/right/bottom.
761  * return FAIL for failure, OK otherwise
762  */
763     int
764 win_split_ins(
765     int		size,
766     int		flags,
767     win_T	*new_wp,
768     int		dir)
769 {
770     win_T	*wp = new_wp;
771     win_T	*oldwin;
772     int		new_size = size;
773     int		i;
774     int		need_status = 0;
775     int		do_equal = FALSE;
776     int		needed;
777     int		available;
778     int		oldwin_height = 0;
779     int		layout;
780     frame_T	*frp, *curfrp, *frp2, *prevfrp;
781     int		before;
782     int		minheight;
783     int		wmh1;
784     int		did_set_fraction = FALSE;
785 
786     if (flags & WSP_TOP)
787 	oldwin = firstwin;
788     else if (flags & WSP_BOT)
789 	oldwin = lastwin;
790     else
791 	oldwin = curwin;
792 
793     /* add a status line when p_ls == 1 and splitting the first window */
794     if (ONE_WINDOW && p_ls == 1 && oldwin->w_status_height == 0)
795     {
796 	if (VISIBLE_HEIGHT(oldwin) <= p_wmh && new_wp == NULL)
797 	{
798 	    emsg(_(e_noroom));
799 	    return FAIL;
800 	}
801 	need_status = STATUS_HEIGHT;
802     }
803 
804 #ifdef FEAT_GUI
805     /* May be needed for the scrollbars that are going to change. */
806     if (gui.in_use)
807 	out_flush();
808 #endif
809 
810     if (flags & WSP_VERT)
811     {
812 	int	wmw1;
813 	int	minwidth;
814 
815 	layout = FR_ROW;
816 
817 	/*
818 	 * Check if we are able to split the current window and compute its
819 	 * width.
820 	 */
821 	/* Current window requires at least 1 space. */
822 	wmw1 = (p_wmw == 0 ? 1 : p_wmw);
823 	needed = wmw1 + 1;
824 	if (flags & WSP_ROOM)
825 	    needed += p_wiw - wmw1;
826 	if (flags & (WSP_BOT | WSP_TOP))
827 	{
828 	    minwidth = frame_minwidth(topframe, NOWIN);
829 	    available = topframe->fr_width;
830 	    needed += minwidth;
831 	}
832 	else if (p_ea)
833 	{
834 	    minwidth = frame_minwidth(oldwin->w_frame, NOWIN);
835 	    prevfrp = oldwin->w_frame;
836 	    for (frp = oldwin->w_frame->fr_parent; frp != NULL;
837 							frp = frp->fr_parent)
838 	    {
839 		if (frp->fr_layout == FR_ROW)
840 		    FOR_ALL_FRAMES(frp2, frp->fr_child)
841 			if (frp2 != prevfrp)
842 			    minwidth += frame_minwidth(frp2, NOWIN);
843 		prevfrp = frp;
844 	    }
845 	    available = topframe->fr_width;
846 	    needed += minwidth;
847 	}
848 	else
849 	{
850 	    minwidth = frame_minwidth(oldwin->w_frame, NOWIN);
851 	    available = oldwin->w_frame->fr_width;
852 	    needed += minwidth;
853 	}
854 	if (available < needed && new_wp == NULL)
855 	{
856 	    emsg(_(e_noroom));
857 	    return FAIL;
858 	}
859 	if (new_size == 0)
860 	    new_size = oldwin->w_width / 2;
861 	if (new_size > available - minwidth - 1)
862 	    new_size = available - minwidth - 1;
863 	if (new_size < wmw1)
864 	    new_size = wmw1;
865 
866 	/* if it doesn't fit in the current window, need win_equal() */
867 	if (oldwin->w_width - new_size - 1 < p_wmw)
868 	    do_equal = TRUE;
869 
870 	/* We don't like to take lines for the new window from a
871 	 * 'winfixwidth' window.  Take them from a window to the left or right
872 	 * instead, if possible. Add one for the separator. */
873 	if (oldwin->w_p_wfw)
874 	    win_setwidth_win(oldwin->w_width + new_size + 1, oldwin);
875 
876 	/* Only make all windows the same width if one of them (except oldwin)
877 	 * is wider than one of the split windows. */
878 	if (!do_equal && p_ea && size == 0 && *p_ead != 'v'
879 	   && oldwin->w_frame->fr_parent != NULL)
880 	{
881 	    frp = oldwin->w_frame->fr_parent->fr_child;
882 	    while (frp != NULL)
883 	    {
884 		if (frp->fr_win != oldwin && frp->fr_win != NULL
885 			&& (frp->fr_win->w_width > new_size
886 			    || frp->fr_win->w_width > oldwin->w_width
887 							      - new_size - 1))
888 		{
889 		    do_equal = TRUE;
890 		    break;
891 		}
892 		frp = frp->fr_next;
893 	    }
894 	}
895     }
896     else
897     {
898 	layout = FR_COL;
899 
900 	/*
901 	 * Check if we are able to split the current window and compute its
902 	 * height.
903 	 */
904 	/* Current window requires at least 1 space. */
905 	wmh1 = (p_wmh == 0 ? 1 : p_wmh) + WINBAR_HEIGHT(curwin);
906 	needed = wmh1 + STATUS_HEIGHT;
907 	if (flags & WSP_ROOM)
908 	    needed += p_wh - wmh1;
909 	if (flags & (WSP_BOT | WSP_TOP))
910 	{
911 	    minheight = frame_minheight(topframe, NOWIN) + need_status;
912 	    available = topframe->fr_height;
913 	    needed += minheight;
914 	}
915 	else if (p_ea)
916 	{
917 	    minheight = frame_minheight(oldwin->w_frame, NOWIN) + need_status;
918 	    prevfrp = oldwin->w_frame;
919 	    for (frp = oldwin->w_frame->fr_parent; frp != NULL;
920 							frp = frp->fr_parent)
921 	    {
922 		if (frp->fr_layout == FR_COL)
923 		    FOR_ALL_FRAMES(frp2, frp->fr_child)
924 			if (frp2 != prevfrp)
925 			    minheight += frame_minheight(frp2, NOWIN);
926 		prevfrp = frp;
927 	    }
928 	    available = topframe->fr_height;
929 	    needed += minheight;
930 	}
931 	else
932 	{
933 	    minheight = frame_minheight(oldwin->w_frame, NOWIN) + need_status;
934 	    available = oldwin->w_frame->fr_height;
935 	    needed += minheight;
936 	}
937 	if (available < needed && new_wp == NULL)
938 	{
939 	    emsg(_(e_noroom));
940 	    return FAIL;
941 	}
942 	oldwin_height = oldwin->w_height;
943 	if (need_status)
944 	{
945 	    oldwin->w_status_height = STATUS_HEIGHT;
946 	    oldwin_height -= STATUS_HEIGHT;
947 	}
948 	if (new_size == 0)
949 	    new_size = oldwin_height / 2;
950 	if (new_size > available - minheight - STATUS_HEIGHT)
951 	    new_size = available - minheight - STATUS_HEIGHT;
952 	if (new_size < wmh1)
953 	    new_size = wmh1;
954 
955 	/* if it doesn't fit in the current window, need win_equal() */
956 	if (oldwin_height - new_size - STATUS_HEIGHT < p_wmh)
957 	    do_equal = TRUE;
958 
959 	/* We don't like to take lines for the new window from a
960 	 * 'winfixheight' window.  Take them from a window above or below
961 	 * instead, if possible. */
962 	if (oldwin->w_p_wfh)
963 	{
964 	    /* Set w_fraction now so that the cursor keeps the same relative
965 	     * vertical position using the old height. */
966 	    set_fraction(oldwin);
967 	    did_set_fraction = TRUE;
968 
969 	    win_setheight_win(oldwin->w_height + new_size + STATUS_HEIGHT,
970 								      oldwin);
971 	    oldwin_height = oldwin->w_height;
972 	    if (need_status)
973 		oldwin_height -= STATUS_HEIGHT;
974 	}
975 
976 	/* Only make all windows the same height if one of them (except oldwin)
977 	 * is higher than one of the split windows. */
978 	if (!do_equal && p_ea && size == 0 && *p_ead != 'h'
979 	   && oldwin->w_frame->fr_parent != NULL)
980 	{
981 	    frp = oldwin->w_frame->fr_parent->fr_child;
982 	    while (frp != NULL)
983 	    {
984 		if (frp->fr_win != oldwin && frp->fr_win != NULL
985 			&& (frp->fr_win->w_height > new_size
986 			    || frp->fr_win->w_height > oldwin_height - new_size
987 							      - STATUS_HEIGHT))
988 		{
989 		    do_equal = TRUE;
990 		    break;
991 		}
992 		frp = frp->fr_next;
993 	    }
994 	}
995     }
996 
997     /*
998      * allocate new window structure and link it in the window list
999      */
1000     if ((flags & WSP_TOP) == 0
1001 	    && ((flags & WSP_BOT)
1002 		|| (flags & WSP_BELOW)
1003 		|| (!(flags & WSP_ABOVE)
1004 		    && ( (flags & WSP_VERT) ? p_spr : p_sb))))
1005     {
1006 	/* new window below/right of current one */
1007 	if (new_wp == NULL)
1008 	    wp = win_alloc(oldwin, FALSE);
1009 	else
1010 	    win_append(oldwin, wp);
1011     }
1012     else
1013     {
1014 	if (new_wp == NULL)
1015 	    wp = win_alloc(oldwin->w_prev, FALSE);
1016 	else
1017 	    win_append(oldwin->w_prev, wp);
1018     }
1019 
1020     if (new_wp == NULL)
1021     {
1022 	if (wp == NULL)
1023 	    return FAIL;
1024 
1025 	new_frame(wp);
1026 	if (wp->w_frame == NULL)
1027 	{
1028 	    win_free(wp, NULL);
1029 	    return FAIL;
1030 	}
1031 
1032 	/* make the contents of the new window the same as the current one */
1033 	win_init(wp, curwin, flags);
1034     }
1035 
1036     /*
1037      * Reorganise the tree of frames to insert the new window.
1038      */
1039     if (flags & (WSP_TOP | WSP_BOT))
1040     {
1041 	if ((topframe->fr_layout == FR_COL && (flags & WSP_VERT) == 0)
1042 	    || (topframe->fr_layout == FR_ROW && (flags & WSP_VERT) != 0))
1043 	{
1044 	    curfrp = topframe->fr_child;
1045 	    if (flags & WSP_BOT)
1046 		while (curfrp->fr_next != NULL)
1047 		    curfrp = curfrp->fr_next;
1048 	}
1049 	else
1050 	    curfrp = topframe;
1051 	before = (flags & WSP_TOP);
1052     }
1053     else
1054     {
1055 	curfrp = oldwin->w_frame;
1056 	if (flags & WSP_BELOW)
1057 	    before = FALSE;
1058 	else if (flags & WSP_ABOVE)
1059 	    before = TRUE;
1060 	else if (flags & WSP_VERT)
1061 	    before = !p_spr;
1062 	else
1063 	    before = !p_sb;
1064     }
1065     if (curfrp->fr_parent == NULL || curfrp->fr_parent->fr_layout != layout)
1066     {
1067 	/* Need to create a new frame in the tree to make a branch. */
1068 	frp = (frame_T *)alloc_clear((unsigned)sizeof(frame_T));
1069 	*frp = *curfrp;
1070 	curfrp->fr_layout = layout;
1071 	frp->fr_parent = curfrp;
1072 	frp->fr_next = NULL;
1073 	frp->fr_prev = NULL;
1074 	curfrp->fr_child = frp;
1075 	curfrp->fr_win = NULL;
1076 	curfrp = frp;
1077 	if (frp->fr_win != NULL)
1078 	    oldwin->w_frame = frp;
1079 	else
1080 	    FOR_ALL_FRAMES(frp, frp->fr_child)
1081 		frp->fr_parent = curfrp;
1082     }
1083 
1084     if (new_wp == NULL)
1085 	frp = wp->w_frame;
1086     else
1087 	frp = new_wp->w_frame;
1088     frp->fr_parent = curfrp->fr_parent;
1089 
1090     /* Insert the new frame at the right place in the frame list. */
1091     if (before)
1092 	frame_insert(curfrp, frp);
1093     else
1094 	frame_append(curfrp, frp);
1095 
1096     /* Set w_fraction now so that the cursor keeps the same relative
1097      * vertical position. */
1098     if (!did_set_fraction)
1099 	set_fraction(oldwin);
1100     wp->w_fraction = oldwin->w_fraction;
1101 
1102     if (flags & WSP_VERT)
1103     {
1104 	wp->w_p_scr = curwin->w_p_scr;
1105 
1106 	if (need_status)
1107 	{
1108 	    win_new_height(oldwin, oldwin->w_height - 1);
1109 	    oldwin->w_status_height = need_status;
1110 	}
1111 	if (flags & (WSP_TOP | WSP_BOT))
1112 	{
1113 	    /* set height and row of new window to full height */
1114 	    wp->w_winrow = tabline_height();
1115 	    win_new_height(wp, curfrp->fr_height - (p_ls > 0)
1116 							  - WINBAR_HEIGHT(wp));
1117 	    wp->w_status_height = (p_ls > 0);
1118 	}
1119 	else
1120 	{
1121 	    /* height and row of new window is same as current window */
1122 	    wp->w_winrow = oldwin->w_winrow;
1123 	    win_new_height(wp, VISIBLE_HEIGHT(oldwin));
1124 	    wp->w_status_height = oldwin->w_status_height;
1125 	}
1126 	frp->fr_height = curfrp->fr_height;
1127 
1128 	/* "new_size" of the current window goes to the new window, use
1129 	 * one column for the vertical separator */
1130 	win_new_width(wp, new_size);
1131 	if (before)
1132 	    wp->w_vsep_width = 1;
1133 	else
1134 	{
1135 	    wp->w_vsep_width = oldwin->w_vsep_width;
1136 	    oldwin->w_vsep_width = 1;
1137 	}
1138 	if (flags & (WSP_TOP | WSP_BOT))
1139 	{
1140 	    if (flags & WSP_BOT)
1141 		frame_add_vsep(curfrp);
1142 	    /* Set width of neighbor frame */
1143 	    frame_new_width(curfrp, curfrp->fr_width
1144 		     - (new_size + ((flags & WSP_TOP) != 0)), flags & WSP_TOP,
1145 								       FALSE);
1146 	}
1147 	else
1148 	    win_new_width(oldwin, oldwin->w_width - (new_size + 1));
1149 	if (before)	/* new window left of current one */
1150 	{
1151 	    wp->w_wincol = oldwin->w_wincol;
1152 	    oldwin->w_wincol += new_size + 1;
1153 	}
1154 	else		/* new window right of current one */
1155 	    wp->w_wincol = oldwin->w_wincol + oldwin->w_width + 1;
1156 	frame_fix_width(oldwin);
1157 	frame_fix_width(wp);
1158     }
1159     else
1160     {
1161 	/* width and column of new window is same as current window */
1162 	if (flags & (WSP_TOP | WSP_BOT))
1163 	{
1164 	    wp->w_wincol = 0;
1165 	    win_new_width(wp, Columns);
1166 	    wp->w_vsep_width = 0;
1167 	}
1168 	else
1169 	{
1170 	    wp->w_wincol = oldwin->w_wincol;
1171 	    win_new_width(wp, oldwin->w_width);
1172 	    wp->w_vsep_width = oldwin->w_vsep_width;
1173 	}
1174 	frp->fr_width = curfrp->fr_width;
1175 
1176 	/* "new_size" of the current window goes to the new window, use
1177 	 * one row for the status line */
1178 	win_new_height(wp, new_size);
1179 	if (flags & (WSP_TOP | WSP_BOT))
1180 	{
1181 	    int new_fr_height = curfrp->fr_height - new_size
1182 							  + WINBAR_HEIGHT(wp) ;
1183 
1184 	    if (!((flags & WSP_BOT) && p_ls == 0))
1185 		new_fr_height -= STATUS_HEIGHT;
1186 	    frame_new_height(curfrp, new_fr_height, flags & WSP_TOP, FALSE);
1187 	}
1188 	else
1189 	    win_new_height(oldwin, oldwin_height - (new_size + STATUS_HEIGHT));
1190 	if (before)	/* new window above current one */
1191 	{
1192 	    wp->w_winrow = oldwin->w_winrow;
1193 	    wp->w_status_height = STATUS_HEIGHT;
1194 	    oldwin->w_winrow += wp->w_height + STATUS_HEIGHT;
1195 	}
1196 	else		/* new window below current one */
1197 	{
1198 	    wp->w_winrow = oldwin->w_winrow + VISIBLE_HEIGHT(oldwin)
1199 							       + STATUS_HEIGHT;
1200 	    wp->w_status_height = oldwin->w_status_height;
1201 	    if (!(flags & WSP_BOT))
1202 		oldwin->w_status_height = STATUS_HEIGHT;
1203 	}
1204 	if (flags & WSP_BOT)
1205 	    frame_add_statusline(curfrp);
1206 	frame_fix_height(wp);
1207 	frame_fix_height(oldwin);
1208     }
1209 
1210     if (flags & (WSP_TOP | WSP_BOT))
1211 	(void)win_comp_pos();
1212 
1213     /*
1214      * Both windows need redrawing
1215      */
1216     redraw_win_later(wp, NOT_VALID);
1217     wp->w_redr_status = TRUE;
1218     redraw_win_later(oldwin, NOT_VALID);
1219     oldwin->w_redr_status = TRUE;
1220 
1221     if (need_status)
1222     {
1223 	msg_row = Rows - 1;
1224 	msg_col = sc_col;
1225 	msg_clr_eos_force();	/* Old command/ruler may still be there */
1226 	comp_col();
1227 	msg_row = Rows - 1;
1228 	msg_col = 0;	/* put position back at start of line */
1229     }
1230 
1231     /*
1232      * equalize the window sizes.
1233      */
1234     if (do_equal || dir != 0)
1235 	win_equal(wp, TRUE,
1236 		(flags & WSP_VERT) ? (dir == 'v' ? 'b' : 'h')
1237 		: dir == 'h' ? 'b' : 'v');
1238 
1239     /* Don't change the window height/width to 'winheight' / 'winwidth' if a
1240      * size was given. */
1241     if (flags & WSP_VERT)
1242     {
1243 	i = p_wiw;
1244 	if (size != 0)
1245 	    p_wiw = size;
1246 
1247 # ifdef FEAT_GUI
1248 	/* When 'guioptions' includes 'L' or 'R' may have to add scrollbars. */
1249 	if (gui.in_use)
1250 	    gui_init_which_components(NULL);
1251 # endif
1252     }
1253     else
1254     {
1255 	i = p_wh;
1256 	if (size != 0)
1257 	    p_wh = size;
1258     }
1259 
1260 #ifdef FEAT_JUMPLIST
1261     /* Keep same changelist position in new window. */
1262     wp->w_changelistidx = oldwin->w_changelistidx;
1263 #endif
1264 
1265     /*
1266      * make the new window the current window
1267      */
1268     win_enter_ext(wp, FALSE, FALSE, TRUE, TRUE, TRUE);
1269     if (flags & WSP_VERT)
1270 	p_wiw = i;
1271     else
1272 	p_wh = i;
1273 
1274     return OK;
1275 }
1276 
1277 
1278 /*
1279  * Initialize window "newp" from window "oldp".
1280  * Used when splitting a window and when creating a new tab page.
1281  * The windows will both edit the same buffer.
1282  * WSP_NEWLOC may be specified in flags to prevent the location list from
1283  * being copied.
1284  */
1285     static void
1286 win_init(win_T *newp, win_T *oldp, int flags UNUSED)
1287 {
1288     int		i;
1289 
1290     newp->w_buffer = oldp->w_buffer;
1291 #ifdef FEAT_SYN_HL
1292     newp->w_s = &(oldp->w_buffer->b_s);
1293 #endif
1294     oldp->w_buffer->b_nwindows++;
1295     newp->w_cursor = oldp->w_cursor;
1296     newp->w_valid = 0;
1297     newp->w_curswant = oldp->w_curswant;
1298     newp->w_set_curswant = oldp->w_set_curswant;
1299     newp->w_topline = oldp->w_topline;
1300 #ifdef FEAT_DIFF
1301     newp->w_topfill = oldp->w_topfill;
1302 #endif
1303     newp->w_leftcol = oldp->w_leftcol;
1304     newp->w_pcmark = oldp->w_pcmark;
1305     newp->w_prev_pcmark = oldp->w_prev_pcmark;
1306     newp->w_alt_fnum = oldp->w_alt_fnum;
1307     newp->w_wrow = oldp->w_wrow;
1308     newp->w_fraction = oldp->w_fraction;
1309     newp->w_prev_fraction_row = oldp->w_prev_fraction_row;
1310 #ifdef FEAT_JUMPLIST
1311     copy_jumplist(oldp, newp);
1312 #endif
1313 #ifdef FEAT_QUICKFIX
1314     if (flags & WSP_NEWLOC)
1315     {
1316 	/* Don't copy the location list.  */
1317 	newp->w_llist = NULL;
1318 	newp->w_llist_ref = NULL;
1319     }
1320     else
1321 	copy_loclist_stack(oldp, newp);
1322 #endif
1323     newp->w_localdir = (oldp->w_localdir == NULL)
1324 				    ? NULL : vim_strsave(oldp->w_localdir);
1325 
1326     /* copy tagstack and folds */
1327     for (i = 0; i < oldp->w_tagstacklen; i++)
1328     {
1329 	newp->w_tagstack[i] = oldp->w_tagstack[i];
1330 	if (newp->w_tagstack[i].tagname != NULL)
1331 	    newp->w_tagstack[i].tagname =
1332 				   vim_strsave(newp->w_tagstack[i].tagname);
1333     }
1334     newp->w_tagstackidx = oldp->w_tagstackidx;
1335     newp->w_tagstacklen = oldp->w_tagstacklen;
1336 #ifdef FEAT_FOLDING
1337     copyFoldingState(oldp, newp);
1338 #endif
1339 
1340     win_init_some(newp, oldp);
1341 
1342 #ifdef FEAT_SYN_HL
1343     check_colorcolumn(newp);
1344 #endif
1345 }
1346 
1347 /*
1348  * Initialize window "newp" from window "old".
1349  * Only the essential things are copied.
1350  */
1351     static void
1352 win_init_some(win_T *newp, win_T *oldp)
1353 {
1354     /* Use the same argument list. */
1355     newp->w_alist = oldp->w_alist;
1356     ++newp->w_alist->al_refcount;
1357     newp->w_arg_idx = oldp->w_arg_idx;
1358 
1359     /* copy options from existing window */
1360     win_copy_options(oldp, newp);
1361 }
1362 
1363 
1364 /*
1365  * Check if "win" is a pointer to an existing window in the current tab page.
1366  */
1367     int
1368 win_valid(win_T *win)
1369 {
1370     win_T	*wp;
1371 
1372     if (win == NULL)
1373 	return FALSE;
1374     FOR_ALL_WINDOWS(wp)
1375 	if (wp == win)
1376 	    return TRUE;
1377     return FALSE;
1378 }
1379 
1380 /*
1381  * Check if "win" is a pointer to an existing window in any tab page.
1382  */
1383     int
1384 win_valid_any_tab(win_T *win)
1385 {
1386     win_T	*wp;
1387     tabpage_T	*tp;
1388 
1389     if (win == NULL)
1390 	return FALSE;
1391     FOR_ALL_TABPAGES(tp)
1392     {
1393 	FOR_ALL_WINDOWS_IN_TAB(tp, wp)
1394 	{
1395 	    if (wp == win)
1396 		return TRUE;
1397 	}
1398     }
1399     return FALSE;
1400 }
1401 
1402 /*
1403  * Return the number of windows.
1404  */
1405     int
1406 win_count(void)
1407 {
1408     win_T	*wp;
1409     int		count = 0;
1410 
1411     FOR_ALL_WINDOWS(wp)
1412 	++count;
1413     return count;
1414 }
1415 
1416 /*
1417  * Make "count" windows on the screen.
1418  * Return actual number of windows on the screen.
1419  * Must be called when there is just one window, filling the whole screen
1420  * (excluding the command line).
1421  */
1422     int
1423 make_windows(
1424     int		count,
1425     int		vertical UNUSED)  /* split windows vertically if TRUE */
1426 {
1427     int		maxcount;
1428     int		todo;
1429 
1430     if (vertical)
1431     {
1432 	/* Each windows needs at least 'winminwidth' lines and a separator
1433 	 * column. */
1434 	maxcount = (curwin->w_width + curwin->w_vsep_width
1435 					     - (p_wiw - p_wmw)) / (p_wmw + 1);
1436     }
1437     else
1438     {
1439 	/* Each window needs at least 'winminheight' lines and a status line. */
1440 	maxcount = (VISIBLE_HEIGHT(curwin) + curwin->w_status_height
1441 				  - (p_wh - p_wmh)) / (p_wmh + STATUS_HEIGHT);
1442     }
1443 
1444     if (maxcount < 2)
1445 	maxcount = 2;
1446     if (count > maxcount)
1447 	count = maxcount;
1448 
1449     /*
1450      * add status line now, otherwise first window will be too big
1451      */
1452     if (count > 1)
1453 	last_status(TRUE);
1454 
1455     /*
1456      * Don't execute autocommands while creating the windows.  Must do that
1457      * when putting the buffers in the windows.
1458      */
1459     block_autocmds();
1460 
1461     /* todo is number of windows left to create */
1462     for (todo = count - 1; todo > 0; --todo)
1463 	if (vertical)
1464 	{
1465 	    if (win_split(curwin->w_width - (curwin->w_width - todo)
1466 			/ (todo + 1) - 1, WSP_VERT | WSP_ABOVE) == FAIL)
1467 		break;
1468 	}
1469 	else
1470 	{
1471 	    if (win_split(curwin->w_height - (curwin->w_height - todo
1472 			    * STATUS_HEIGHT) / (todo + 1)
1473 			- STATUS_HEIGHT, WSP_ABOVE) == FAIL)
1474 		break;
1475 	}
1476 
1477     unblock_autocmds();
1478 
1479     /* return actual number of windows */
1480     return (count - todo);
1481 }
1482 
1483 /*
1484  * Exchange current and next window
1485  */
1486     static void
1487 win_exchange(long Prenum)
1488 {
1489     frame_T	*frp;
1490     frame_T	*frp2;
1491     win_T	*wp;
1492     win_T	*wp2;
1493     int		temp;
1494 
1495     if (ONE_WINDOW)	    /* just one window */
1496     {
1497 	beep_flush();
1498 	return;
1499     }
1500 
1501 #ifdef FEAT_GUI
1502     need_mouse_correct = TRUE;
1503 #endif
1504 
1505     /*
1506      * find window to exchange with
1507      */
1508     if (Prenum)
1509     {
1510 	frp = curwin->w_frame->fr_parent->fr_child;
1511 	while (frp != NULL && --Prenum > 0)
1512 	    frp = frp->fr_next;
1513     }
1514     else if (curwin->w_frame->fr_next != NULL)	/* Swap with next */
1515 	frp = curwin->w_frame->fr_next;
1516     else    /* Swap last window in row/col with previous */
1517 	frp = curwin->w_frame->fr_prev;
1518 
1519     /* We can only exchange a window with another window, not with a frame
1520      * containing windows. */
1521     if (frp == NULL || frp->fr_win == NULL || frp->fr_win == curwin)
1522 	return;
1523     wp = frp->fr_win;
1524 
1525 /*
1526  * 1. remove curwin from the list. Remember after which window it was in wp2
1527  * 2. insert curwin before wp in the list
1528  * if wp != wp2
1529  *    3. remove wp from the list
1530  *    4. insert wp after wp2
1531  * 5. exchange the status line height and vsep width.
1532  */
1533     wp2 = curwin->w_prev;
1534     frp2 = curwin->w_frame->fr_prev;
1535     if (wp->w_prev != curwin)
1536     {
1537 	win_remove(curwin, NULL);
1538 	frame_remove(curwin->w_frame);
1539 	win_append(wp->w_prev, curwin);
1540 	frame_insert(frp, curwin->w_frame);
1541     }
1542     if (wp != wp2)
1543     {
1544 	win_remove(wp, NULL);
1545 	frame_remove(wp->w_frame);
1546 	win_append(wp2, wp);
1547 	if (frp2 == NULL)
1548 	    frame_insert(wp->w_frame->fr_parent->fr_child, wp->w_frame);
1549 	else
1550 	    frame_append(frp2, wp->w_frame);
1551     }
1552     temp = curwin->w_status_height;
1553     curwin->w_status_height = wp->w_status_height;
1554     wp->w_status_height = temp;
1555     temp = curwin->w_vsep_width;
1556     curwin->w_vsep_width = wp->w_vsep_width;
1557     wp->w_vsep_width = temp;
1558 
1559     /* If the windows are not in the same frame, exchange the sizes to avoid
1560      * messing up the window layout.  Otherwise fix the frame sizes. */
1561     if (curwin->w_frame->fr_parent != wp->w_frame->fr_parent)
1562     {
1563 	temp = curwin->w_height;
1564 	curwin->w_height = wp->w_height;
1565 	wp->w_height = temp;
1566 	temp = curwin->w_width;
1567 	curwin->w_width = wp->w_width;
1568 	wp->w_width = temp;
1569     }
1570     else
1571     {
1572 	frame_fix_height(curwin);
1573 	frame_fix_height(wp);
1574 	frame_fix_width(curwin);
1575 	frame_fix_width(wp);
1576     }
1577 
1578     (void)win_comp_pos();		/* recompute window positions */
1579 
1580     win_enter(wp, TRUE);
1581     redraw_all_later(NOT_VALID);
1582 }
1583 
1584 /*
1585  * rotate windows: if upwards TRUE the second window becomes the first one
1586  *		   if upwards FALSE the first window becomes the second one
1587  */
1588     static void
1589 win_rotate(int upwards, int count)
1590 {
1591     win_T	*wp1;
1592     win_T	*wp2;
1593     frame_T	*frp;
1594     int		n;
1595 
1596     if (ONE_WINDOW)		/* nothing to do */
1597     {
1598 	beep_flush();
1599 	return;
1600     }
1601 
1602 #ifdef FEAT_GUI
1603     need_mouse_correct = TRUE;
1604 #endif
1605 
1606     /* Check if all frames in this row/col have one window. */
1607     FOR_ALL_FRAMES(frp, curwin->w_frame->fr_parent->fr_child)
1608 	if (frp->fr_win == NULL)
1609 	{
1610 	    emsg(_("E443: Cannot rotate when another window is split"));
1611 	    return;
1612 	}
1613 
1614     while (count--)
1615     {
1616 	if (upwards)		/* first window becomes last window */
1617 	{
1618 	    /* remove first window/frame from the list */
1619 	    frp = curwin->w_frame->fr_parent->fr_child;
1620 	    wp1 = frp->fr_win;
1621 	    win_remove(wp1, NULL);
1622 	    frame_remove(frp);
1623 
1624 	    /* find last frame and append removed window/frame after it */
1625 	    for ( ; frp->fr_next != NULL; frp = frp->fr_next)
1626 		;
1627 	    win_append(frp->fr_win, wp1);
1628 	    frame_append(frp, wp1->w_frame);
1629 
1630 	    wp2 = frp->fr_win;		/* previously last window */
1631 	}
1632 	else			/* last window becomes first window */
1633 	{
1634 	    /* find last window/frame in the list and remove it */
1635 	    for (frp = curwin->w_frame; frp->fr_next != NULL;
1636 							   frp = frp->fr_next)
1637 		;
1638 	    wp1 = frp->fr_win;
1639 	    wp2 = wp1->w_prev;		    /* will become last window */
1640 	    win_remove(wp1, NULL);
1641 	    frame_remove(frp);
1642 
1643 	    /* append the removed window/frame before the first in the list */
1644 	    win_append(frp->fr_parent->fr_child->fr_win->w_prev, wp1);
1645 	    frame_insert(frp->fr_parent->fr_child, frp);
1646 	}
1647 
1648 	/* exchange status height and vsep width of old and new last window */
1649 	n = wp2->w_status_height;
1650 	wp2->w_status_height = wp1->w_status_height;
1651 	wp1->w_status_height = n;
1652 	frame_fix_height(wp1);
1653 	frame_fix_height(wp2);
1654 	n = wp2->w_vsep_width;
1655 	wp2->w_vsep_width = wp1->w_vsep_width;
1656 	wp1->w_vsep_width = n;
1657 	frame_fix_width(wp1);
1658 	frame_fix_width(wp2);
1659 
1660 	/* recompute w_winrow and w_wincol for all windows */
1661 	(void)win_comp_pos();
1662     }
1663 
1664     redraw_all_later(NOT_VALID);
1665 }
1666 
1667 /*
1668  * Move the current window to the very top/bottom/left/right of the screen.
1669  */
1670     static void
1671 win_totop(int size, int flags)
1672 {
1673     int		dir;
1674     int		height = curwin->w_height;
1675 
1676     if (ONE_WINDOW)
1677     {
1678 	beep_flush();
1679 	return;
1680     }
1681 
1682     /* Remove the window and frame from the tree of frames. */
1683     (void)winframe_remove(curwin, &dir, NULL);
1684     win_remove(curwin, NULL);
1685     last_status(FALSE);	    /* may need to remove last status line */
1686     (void)win_comp_pos();   /* recompute window positions */
1687 
1688     /* Split a window on the desired side and put the window there. */
1689     (void)win_split_ins(size, flags, curwin, dir);
1690     if (!(flags & WSP_VERT))
1691     {
1692 	win_setheight(height);
1693 	if (p_ea)
1694 	    win_equal(curwin, TRUE, 'v');
1695     }
1696 
1697 #if defined(FEAT_GUI)
1698     /* When 'guioptions' includes 'L' or 'R' may have to remove or add
1699      * scrollbars.  Have to update them anyway. */
1700     gui_may_update_scrollbars();
1701 #endif
1702 }
1703 
1704 /*
1705  * Move window "win1" to below/right of "win2" and make "win1" the current
1706  * window.  Only works within the same frame!
1707  */
1708     void
1709 win_move_after(win_T *win1, win_T *win2)
1710 {
1711     int		height;
1712 
1713     /* check if the arguments are reasonable */
1714     if (win1 == win2)
1715 	return;
1716 
1717     /* check if there is something to do */
1718     if (win2->w_next != win1)
1719     {
1720 	/* may need move the status line/vertical separator of the last window
1721 	 * */
1722 	if (win1 == lastwin)
1723 	{
1724 	    height = win1->w_prev->w_status_height;
1725 	    win1->w_prev->w_status_height = win1->w_status_height;
1726 	    win1->w_status_height = height;
1727 	    if (win1->w_prev->w_vsep_width == 1)
1728 	    {
1729 		/* Remove the vertical separator from the last-but-one window,
1730 		 * add it to the last window.  Adjust the frame widths. */
1731 		win1->w_prev->w_vsep_width = 0;
1732 		win1->w_prev->w_frame->fr_width -= 1;
1733 		win1->w_vsep_width = 1;
1734 		win1->w_frame->fr_width += 1;
1735 	    }
1736 	}
1737 	else if (win2 == lastwin)
1738 	{
1739 	    height = win1->w_status_height;
1740 	    win1->w_status_height = win2->w_status_height;
1741 	    win2->w_status_height = height;
1742 	    if (win1->w_vsep_width == 1)
1743 	    {
1744 		/* Remove the vertical separator from win1, add it to the last
1745 		 * window, win2.  Adjust the frame widths. */
1746 		win2->w_vsep_width = 1;
1747 		win2->w_frame->fr_width += 1;
1748 		win1->w_vsep_width = 0;
1749 		win1->w_frame->fr_width -= 1;
1750 	    }
1751 	}
1752 	win_remove(win1, NULL);
1753 	frame_remove(win1->w_frame);
1754 	win_append(win2, win1);
1755 	frame_append(win2->w_frame, win1->w_frame);
1756 
1757 	(void)win_comp_pos();	/* recompute w_winrow for all windows */
1758 	redraw_later(NOT_VALID);
1759     }
1760     win_enter(win1, FALSE);
1761 }
1762 
1763 /*
1764  * Make all windows the same height.
1765  * 'next_curwin' will soon be the current window, make sure it has enough
1766  * rows.
1767  */
1768     void
1769 win_equal(
1770     win_T	*next_curwin,	/* pointer to current window to be or NULL */
1771     int		current,	/* do only frame with current window */
1772     int		dir)		/* 'v' for vertically, 'h' for horizontally,
1773 				   'b' for both, 0 for using p_ead */
1774 {
1775     if (dir == 0)
1776 	dir = *p_ead;
1777     win_equal_rec(next_curwin == NULL ? curwin : next_curwin, current,
1778 		      topframe, dir, 0, tabline_height(),
1779 					   (int)Columns, topframe->fr_height);
1780 }
1781 
1782 /*
1783  * Set a frame to a new position and height, spreading the available room
1784  * equally over contained frames.
1785  * The window "next_curwin" (if not NULL) should at least get the size from
1786  * 'winheight' and 'winwidth' if possible.
1787  */
1788     static void
1789 win_equal_rec(
1790     win_T	*next_curwin,	/* pointer to current window to be or NULL */
1791     int		current,	/* do only frame with current window */
1792     frame_T	*topfr,		/* frame to set size off */
1793     int		dir,		/* 'v', 'h' or 'b', see win_equal() */
1794     int		col,		/* horizontal position for frame */
1795     int		row,		/* vertical position for frame */
1796     int		width,		/* new width of frame */
1797     int		height)		/* new height of frame */
1798 {
1799     int		n, m;
1800     int		extra_sep = 0;
1801     int		wincount, totwincount = 0;
1802     frame_T	*fr;
1803     int		next_curwin_size = 0;
1804     int		room = 0;
1805     int		new_size;
1806     int		has_next_curwin = 0;
1807     int		hnc;
1808 
1809     if (topfr->fr_layout == FR_LEAF)
1810     {
1811 	/* Set the width/height of this frame.
1812 	 * Redraw when size or position changes */
1813 	if (topfr->fr_height != height || topfr->fr_win->w_winrow != row
1814 		|| topfr->fr_width != width || topfr->fr_win->w_wincol != col
1815 	   )
1816 	{
1817 	    topfr->fr_win->w_winrow = row;
1818 	    frame_new_height(topfr, height, FALSE, FALSE);
1819 	    topfr->fr_win->w_wincol = col;
1820 	    frame_new_width(topfr, width, FALSE, FALSE);
1821 	    redraw_all_later(NOT_VALID);
1822 	}
1823     }
1824     else if (topfr->fr_layout == FR_ROW)
1825     {
1826 	topfr->fr_width = width;
1827 	topfr->fr_height = height;
1828 
1829 	if (dir != 'v')			/* equalize frame widths */
1830 	{
1831 	    /* Compute the maximum number of windows horizontally in this
1832 	     * frame. */
1833 	    n = frame_minwidth(topfr, NOWIN);
1834 	    /* add one for the rightmost window, it doesn't have a separator */
1835 	    if (col + width == Columns)
1836 		extra_sep = 1;
1837 	    else
1838 		extra_sep = 0;
1839 	    totwincount = (n + extra_sep) / (p_wmw + 1);
1840 	    has_next_curwin = frame_has_win(topfr, next_curwin);
1841 
1842 	    /*
1843 	     * Compute width for "next_curwin" window and room available for
1844 	     * other windows.
1845 	     * "m" is the minimal width when counting p_wiw for "next_curwin".
1846 	     */
1847 	    m = frame_minwidth(topfr, next_curwin);
1848 	    room = width - m;
1849 	    if (room < 0)
1850 	    {
1851 		next_curwin_size = p_wiw + room;
1852 		room = 0;
1853 	    }
1854 	    else
1855 	    {
1856 		next_curwin_size = -1;
1857 		FOR_ALL_FRAMES(fr, topfr->fr_child)
1858 		{
1859 		    /* If 'winfixwidth' set keep the window width if
1860 		     * possible.
1861 		     * Watch out for this window being the next_curwin. */
1862 		    if (frame_fixed_width(fr))
1863 		    {
1864 			n = frame_minwidth(fr, NOWIN);
1865 			new_size = fr->fr_width;
1866 			if (frame_has_win(fr, next_curwin))
1867 			{
1868 			    room += p_wiw - p_wmw;
1869 			    next_curwin_size = 0;
1870 			    if (new_size < p_wiw)
1871 				new_size = p_wiw;
1872 			}
1873 			else
1874 			    /* These windows don't use up room. */
1875 			    totwincount -= (n + (fr->fr_next == NULL
1876 					      ? extra_sep : 0)) / (p_wmw + 1);
1877 			room -= new_size - n;
1878 			if (room < 0)
1879 			{
1880 			    new_size += room;
1881 			    room = 0;
1882 			}
1883 			fr->fr_newwidth = new_size;
1884 		    }
1885 		}
1886 		if (next_curwin_size == -1)
1887 		{
1888 		    if (!has_next_curwin)
1889 			next_curwin_size = 0;
1890 		    else if (totwincount > 1
1891 			    && (room + (totwincount - 2))
1892 						  / (totwincount - 1) > p_wiw)
1893 		    {
1894 			/* Can make all windows wider than 'winwidth', spread
1895 			 * the room equally. */
1896 			next_curwin_size = (room + p_wiw
1897 					    + (totwincount - 1) * p_wmw
1898 					    + (totwincount - 1)) / totwincount;
1899 			room -= next_curwin_size - p_wiw;
1900 		    }
1901 		    else
1902 			next_curwin_size = p_wiw;
1903 		}
1904 	    }
1905 
1906 	    if (has_next_curwin)
1907 		--totwincount;		/* don't count curwin */
1908 	}
1909 
1910 	FOR_ALL_FRAMES(fr, topfr->fr_child)
1911 	{
1912 	    wincount = 1;
1913 	    if (fr->fr_next == NULL)
1914 		/* last frame gets all that remains (avoid roundoff error) */
1915 		new_size = width;
1916 	    else if (dir == 'v')
1917 		new_size = fr->fr_width;
1918 	    else if (frame_fixed_width(fr))
1919 	    {
1920 		new_size = fr->fr_newwidth;
1921 		wincount = 0;	    /* doesn't count as a sizeable window */
1922 	    }
1923 	    else
1924 	    {
1925 		/* Compute the maximum number of windows horiz. in "fr". */
1926 		n = frame_minwidth(fr, NOWIN);
1927 		wincount = (n + (fr->fr_next == NULL ? extra_sep : 0))
1928 								/ (p_wmw + 1);
1929 		m = frame_minwidth(fr, next_curwin);
1930 		if (has_next_curwin)
1931 		    hnc = frame_has_win(fr, next_curwin);
1932 		else
1933 		    hnc = FALSE;
1934 		if (hnc)	    /* don't count next_curwin */
1935 		    --wincount;
1936 		if (totwincount == 0)
1937 		    new_size = room;
1938 		else
1939 		    new_size = (wincount * room + ((unsigned)totwincount >> 1))
1940 								/ totwincount;
1941 		if (hnc)	    /* add next_curwin size */
1942 		{
1943 		    next_curwin_size -= p_wiw - (m - n);
1944 		    new_size += next_curwin_size;
1945 		    room -= new_size - next_curwin_size;
1946 		}
1947 		else
1948 		    room -= new_size;
1949 		new_size += n;
1950 	    }
1951 
1952 	    /* Skip frame that is full width when splitting or closing a
1953 	     * window, unless equalizing all frames. */
1954 	    if (!current || dir != 'v' || topfr->fr_parent != NULL
1955 		    || (new_size != fr->fr_width)
1956 		    || frame_has_win(fr, next_curwin))
1957 		win_equal_rec(next_curwin, current, fr, dir, col, row,
1958 							    new_size, height);
1959 	    col += new_size;
1960 	    width -= new_size;
1961 	    totwincount -= wincount;
1962 	}
1963     }
1964     else /* topfr->fr_layout == FR_COL */
1965     {
1966 	topfr->fr_width = width;
1967 	topfr->fr_height = height;
1968 
1969 	if (dir != 'h')			/* equalize frame heights */
1970 	{
1971 	    /* Compute maximum number of windows vertically in this frame. */
1972 	    n = frame_minheight(topfr, NOWIN);
1973 	    /* add one for the bottom window if it doesn't have a statusline */
1974 	    if (row + height == cmdline_row && p_ls == 0)
1975 		extra_sep = 1;
1976 	    else
1977 		extra_sep = 0;
1978 	    totwincount = (n + extra_sep) / (p_wmh + 1);
1979 	    has_next_curwin = frame_has_win(topfr, next_curwin);
1980 
1981 	    /*
1982 	     * Compute height for "next_curwin" window and room available for
1983 	     * other windows.
1984 	     * "m" is the minimal height when counting p_wh for "next_curwin".
1985 	     */
1986 	    m = frame_minheight(topfr, next_curwin);
1987 	    room = height - m;
1988 	    if (room < 0)
1989 	    {
1990 		/* The room is less then 'winheight', use all space for the
1991 		 * current window. */
1992 		next_curwin_size = p_wh + room;
1993 		room = 0;
1994 	    }
1995 	    else
1996 	    {
1997 		next_curwin_size = -1;
1998 		FOR_ALL_FRAMES(fr, topfr->fr_child)
1999 		{
2000 		    /* If 'winfixheight' set keep the window height if
2001 		     * possible.
2002 		     * Watch out for this window being the next_curwin. */
2003 		    if (frame_fixed_height(fr))
2004 		    {
2005 			n = frame_minheight(fr, NOWIN);
2006 			new_size = fr->fr_height;
2007 			if (frame_has_win(fr, next_curwin))
2008 			{
2009 			    room += p_wh - p_wmh;
2010 			    next_curwin_size = 0;
2011 			    if (new_size < p_wh)
2012 				new_size = p_wh;
2013 			}
2014 			else
2015 			    /* These windows don't use up room. */
2016 			    totwincount -= (n + (fr->fr_next == NULL
2017 					      ? extra_sep : 0)) / (p_wmh + 1);
2018 			room -= new_size - n;
2019 			if (room < 0)
2020 			{
2021 			    new_size += room;
2022 			    room = 0;
2023 			}
2024 			fr->fr_newheight = new_size;
2025 		    }
2026 		}
2027 		if (next_curwin_size == -1)
2028 		{
2029 		    if (!has_next_curwin)
2030 			next_curwin_size = 0;
2031 		    else if (totwincount > 1
2032 			    && (room + (totwincount - 2))
2033 						   / (totwincount - 1) > p_wh)
2034 		    {
2035 			/* can make all windows higher than 'winheight',
2036 			 * spread the room equally. */
2037 			next_curwin_size = (room + p_wh
2038 					   + (totwincount - 1) * p_wmh
2039 					   + (totwincount - 1)) / totwincount;
2040 			room -= next_curwin_size - p_wh;
2041 		    }
2042 		    else
2043 			next_curwin_size = p_wh;
2044 		}
2045 	    }
2046 
2047 	    if (has_next_curwin)
2048 		--totwincount;		/* don't count curwin */
2049 	}
2050 
2051 	FOR_ALL_FRAMES(fr, topfr->fr_child)
2052 	{
2053 	    wincount = 1;
2054 	    if (fr->fr_next == NULL)
2055 		/* last frame gets all that remains (avoid roundoff error) */
2056 		new_size = height;
2057 	    else if (dir == 'h')
2058 		new_size = fr->fr_height;
2059 	    else if (frame_fixed_height(fr))
2060 	    {
2061 		new_size = fr->fr_newheight;
2062 		wincount = 0;	    /* doesn't count as a sizeable window */
2063 	    }
2064 	    else
2065 	    {
2066 		/* Compute the maximum number of windows vert. in "fr". */
2067 		n = frame_minheight(fr, NOWIN);
2068 		wincount = (n + (fr->fr_next == NULL ? extra_sep : 0))
2069 								/ (p_wmh + 1);
2070 		m = frame_minheight(fr, next_curwin);
2071 		if (has_next_curwin)
2072 		    hnc = frame_has_win(fr, next_curwin);
2073 		else
2074 		    hnc = FALSE;
2075 		if (hnc)	    /* don't count next_curwin */
2076 		    --wincount;
2077 		if (totwincount == 0)
2078 		    new_size = room;
2079 		else
2080 		    new_size = (wincount * room + ((unsigned)totwincount >> 1))
2081 								/ totwincount;
2082 		if (hnc)	    /* add next_curwin size */
2083 		{
2084 		    next_curwin_size -= p_wh - (m - n);
2085 		    new_size += next_curwin_size;
2086 		    room -= new_size - next_curwin_size;
2087 		}
2088 		else
2089 		    room -= new_size;
2090 		new_size += n;
2091 	    }
2092 	    /* Skip frame that is full width when splitting or closing a
2093 	     * window, unless equalizing all frames. */
2094 	    if (!current || dir != 'h' || topfr->fr_parent != NULL
2095 		    || (new_size != fr->fr_height)
2096 		    || frame_has_win(fr, next_curwin))
2097 		win_equal_rec(next_curwin, current, fr, dir, col, row,
2098 							     width, new_size);
2099 	    row += new_size;
2100 	    height -= new_size;
2101 	    totwincount -= wincount;
2102 	}
2103     }
2104 }
2105 
2106 #ifdef FEAT_JOB_CHANNEL
2107     static void
2108 leaving_window(win_T *win)
2109 {
2110     // Only matters for a prompt window.
2111     if (!bt_prompt(win->w_buffer))
2112 	return;
2113 
2114     // When leaving a prompt window stop Insert mode and perhaps restart
2115     // it when entering that window again.
2116     win->w_buffer->b_prompt_insert = restart_edit;
2117     if (restart_edit != 0 && mode_displayed)
2118 	clear_cmdline = TRUE;		/* unshow mode later */
2119     restart_edit = NUL;
2120 
2121     // When leaving the window (or closing the window) was done from a
2122     // callback we need to break out of the Insert mode loop and restart Insert
2123     // mode when entering the window again.
2124     if (State & INSERT)
2125     {
2126 	stop_insert_mode = TRUE;
2127 	if (win->w_buffer->b_prompt_insert == NUL)
2128 	    win->w_buffer->b_prompt_insert = 'A';
2129     }
2130 }
2131 
2132     static void
2133 entering_window(win_T *win)
2134 {
2135     // Only matters for a prompt window.
2136     if (!bt_prompt(win->w_buffer))
2137 	return;
2138 
2139     // When switching to a prompt buffer that was in Insert mode, don't stop
2140     // Insert mode, it may have been set in leaving_window().
2141     if (win->w_buffer->b_prompt_insert != NUL)
2142 	stop_insert_mode = FALSE;
2143 
2144     // When entering the prompt window restart Insert mode if we were in Insert
2145     // mode when we left it.
2146     restart_edit = win->w_buffer->b_prompt_insert;
2147 }
2148 #endif
2149 
2150 /*
2151  * Close all windows for buffer "buf".
2152  */
2153     void
2154 close_windows(
2155     buf_T	*buf,
2156     int		keep_curwin)	    /* don't close "curwin" */
2157 {
2158     win_T	*wp;
2159     tabpage_T   *tp, *nexttp;
2160     int		h = tabline_height();
2161     int		count = tabpage_index(NULL);
2162 
2163     ++RedrawingDisabled;
2164 
2165     for (wp = firstwin; wp != NULL && !ONE_WINDOW; )
2166     {
2167 	if (wp->w_buffer == buf && (!keep_curwin || wp != curwin)
2168 		&& !(wp->w_closing || wp->w_buffer->b_locked > 0))
2169 	{
2170 	    if (win_close(wp, FALSE) == FAIL)
2171 		/* If closing the window fails give up, to avoid looping
2172 		 * forever. */
2173 		break;
2174 
2175 	    /* Start all over, autocommands may change the window layout. */
2176 	    wp = firstwin;
2177 	}
2178 	else
2179 	    wp = wp->w_next;
2180     }
2181 
2182     /* Also check windows in other tab pages. */
2183     for (tp = first_tabpage; tp != NULL; tp = nexttp)
2184     {
2185 	nexttp = tp->tp_next;
2186 	if (tp != curtab)
2187 	    for (wp = tp->tp_firstwin; wp != NULL; wp = wp->w_next)
2188 		if (wp->w_buffer == buf
2189 		    && !(wp->w_closing || wp->w_buffer->b_locked > 0))
2190 		{
2191 		    win_close_othertab(wp, FALSE, tp);
2192 
2193 		    /* Start all over, the tab page may be closed and
2194 		     * autocommands may change the window layout. */
2195 		    nexttp = first_tabpage;
2196 		    break;
2197 		}
2198     }
2199 
2200     --RedrawingDisabled;
2201 
2202     if (count != tabpage_index(NULL))
2203 	apply_autocmds(EVENT_TABCLOSED, NULL, NULL, FALSE, curbuf);
2204 
2205     redraw_tabline = TRUE;
2206     if (h != tabline_height())
2207 	shell_new_rows();
2208 }
2209 
2210 /*
2211  * Return TRUE if the current window is the only window that exists (ignoring
2212  * "aucmd_win").
2213  * Returns FALSE if there is a window, possibly in another tab page.
2214  */
2215     static int
2216 last_window(void)
2217 {
2218     return (one_window() && first_tabpage->tp_next == NULL);
2219 }
2220 
2221 /*
2222  * Return TRUE if there is only one window other than "aucmd_win" in the
2223  * current tab page.
2224  */
2225     int
2226 one_window(void)
2227 {
2228     win_T	*wp;
2229     int		seen_one = FALSE;
2230 
2231     FOR_ALL_WINDOWS(wp)
2232     {
2233 	if (wp != aucmd_win)
2234 	{
2235 	    if (seen_one)
2236 		return FALSE;
2237 	    seen_one = TRUE;
2238 	}
2239     }
2240     return TRUE;
2241 }
2242 
2243 /*
2244  * Close the possibly last window in a tab page.
2245  * Returns TRUE when the window was closed already.
2246  */
2247     static int
2248 close_last_window_tabpage(
2249     win_T	*win,
2250     int		free_buf,
2251     tabpage_T   *prev_curtab)
2252 {
2253     if (ONE_WINDOW)
2254     {
2255 	buf_T	*old_curbuf = curbuf;
2256 
2257 	/*
2258 	 * Closing the last window in a tab page.  First go to another tab
2259 	 * page and then close the window and the tab page.  This avoids that
2260 	 * curwin and curtab are invalid while we are freeing memory, they may
2261 	 * be used in GUI events.
2262 	 * Don't trigger autocommands yet, they may use wrong values, so do
2263 	 * that below.
2264 	 */
2265 	goto_tabpage_tp(alt_tabpage(), FALSE, TRUE);
2266 	redraw_tabline = TRUE;
2267 
2268 	/* Safety check: Autocommands may have closed the window when jumping
2269 	 * to the other tab page. */
2270 	if (valid_tabpage(prev_curtab) && prev_curtab->tp_firstwin == win)
2271 	{
2272 	    int	    h = tabline_height();
2273 
2274 	    win_close_othertab(win, free_buf, prev_curtab);
2275 	    if (h != tabline_height())
2276 		shell_new_rows();
2277 	}
2278 #ifdef FEAT_JOB_CHANNEL
2279 	entering_window(curwin);
2280 #endif
2281 	/* Since goto_tabpage_tp above did not trigger *Enter autocommands, do
2282 	 * that now. */
2283 	apply_autocmds(EVENT_TABCLOSED, NULL, NULL, FALSE, curbuf);
2284 	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
2285 	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
2286 	if (old_curbuf != curbuf)
2287 	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
2288 	return TRUE;
2289     }
2290     return FALSE;
2291 }
2292 
2293 /*
2294  * Close window "win".  Only works for the current tab page.
2295  * If "free_buf" is TRUE related buffer may be unloaded.
2296  *
2297  * Called by :quit, :close, :xit, :wq and findtag().
2298  * Returns FAIL when the window was not closed.
2299  */
2300     int
2301 win_close(win_T *win, int free_buf)
2302 {
2303     win_T	*wp;
2304     int		other_buffer = FALSE;
2305     int		close_curwin = FALSE;
2306     int		dir;
2307     int		help_window = FALSE;
2308     tabpage_T   *prev_curtab = curtab;
2309     frame_T	*win_frame = win->w_frame->fr_parent;
2310 
2311     if (last_window())
2312     {
2313 	emsg(_("E444: Cannot close last window"));
2314 	return FAIL;
2315     }
2316 
2317     if (win->w_closing || (win->w_buffer != NULL
2318 					       && win->w_buffer->b_locked > 0))
2319 	return FAIL; /* window is already being closed */
2320     if (win == aucmd_win)
2321     {
2322 	emsg(_("E813: Cannot close autocmd window"));
2323 	return FAIL;
2324     }
2325     if ((firstwin == aucmd_win || lastwin == aucmd_win) && one_window())
2326     {
2327 	emsg(_("E814: Cannot close window, only autocmd window would remain"));
2328 	return FAIL;
2329     }
2330 
2331     /* When closing the last window in a tab page first go to another tab page
2332      * and then close the window and the tab page to avoid that curwin and
2333      * curtab are invalid while we are freeing memory. */
2334     if (close_last_window_tabpage(win, free_buf, prev_curtab))
2335       return FAIL;
2336 
2337     /* When closing the help window, try restoring a snapshot after closing
2338      * the window.  Otherwise clear the snapshot, it's now invalid. */
2339     if (bt_help(win->w_buffer))
2340 	help_window = TRUE;
2341     else
2342 	clear_snapshot(curtab, SNAP_HELP_IDX);
2343 
2344     if (win == curwin)
2345     {
2346 #ifdef FEAT_JOB_CHANNEL
2347 	leaving_window(curwin);
2348 #endif
2349 	/*
2350 	 * Guess which window is going to be the new current window.
2351 	 * This may change because of the autocommands (sigh).
2352 	 */
2353 	wp = frame2win(win_altframe(win, NULL));
2354 
2355 	/*
2356 	 * Be careful: If autocommands delete the window or cause this window
2357 	 * to be the last one left, return now.
2358 	 */
2359 	if (wp->w_buffer != curbuf)
2360 	{
2361 	    other_buffer = TRUE;
2362 	    win->w_closing = TRUE;
2363 	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
2364 	    if (!win_valid(win))
2365 		return FAIL;
2366 	    win->w_closing = FALSE;
2367 	    if (last_window())
2368 		return FAIL;
2369 	}
2370 	win->w_closing = TRUE;
2371 	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
2372 	if (!win_valid(win))
2373 	    return FAIL;
2374 	win->w_closing = FALSE;
2375 	if (last_window())
2376 	    return FAIL;
2377 #ifdef FEAT_EVAL
2378 	/* autocmds may abort script processing */
2379 	if (aborting())
2380 	    return FAIL;
2381 #endif
2382     }
2383 
2384 #ifdef FEAT_GUI
2385     /* Avoid trouble with scrollbars that are going to be deleted in
2386      * win_free(). */
2387     if (gui.in_use)
2388 	out_flush();
2389 #endif
2390 
2391 #ifdef FEAT_SYN_HL
2392     /* Free independent synblock before the buffer is freed. */
2393     if (win->w_buffer != NULL)
2394 	reset_synblock(win);
2395 #endif
2396 
2397     /*
2398      * Close the link to the buffer.
2399      */
2400     if (win->w_buffer != NULL)
2401     {
2402 	bufref_T    bufref;
2403 
2404 	set_bufref(&bufref, curbuf);
2405 	win->w_closing = TRUE;
2406 	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, TRUE);
2407 	if (win_valid_any_tab(win))
2408 	    win->w_closing = FALSE;
2409 	/* Make sure curbuf is valid. It can become invalid if 'bufhidden' is
2410 	 * "wipe". */
2411 	if (!bufref_valid(&bufref))
2412 	    curbuf = firstbuf;
2413     }
2414 
2415     if (only_one_window() && win_valid(win) && win->w_buffer == NULL
2416 	    && (last_window() || curtab != prev_curtab
2417 		|| close_last_window_tabpage(win, free_buf, prev_curtab)))
2418     {
2419 	/* Autocommands have closed all windows, quit now.  Restore
2420 	 * curwin->w_buffer, otherwise writing viminfo may fail. */
2421 	if (curwin->w_buffer == NULL)
2422 	    curwin->w_buffer = curbuf;
2423 	getout(0);
2424     }
2425 
2426     /* Autocommands may have moved to another tab page. */
2427     if (curtab != prev_curtab && win_valid_any_tab(win)
2428 						      && win->w_buffer == NULL)
2429     {
2430 	/* Need to close the window anyway, since the buffer is NULL. */
2431 	win_close_othertab(win, FALSE, prev_curtab);
2432 	return FAIL;
2433     }
2434 
2435     /* Autocommands may have closed the window already or closed the only
2436      * other window. */
2437     if (!win_valid(win) || last_window()
2438 	    || close_last_window_tabpage(win, free_buf, prev_curtab))
2439 	return FAIL;
2440 
2441     /* Free the memory used for the window and get the window that received
2442      * the screen space. */
2443     wp = win_free_mem(win, &dir, NULL);
2444 
2445     /* Make sure curwin isn't invalid.  It can cause severe trouble when
2446      * printing an error message.  For win_equal() curbuf needs to be valid
2447      * too. */
2448     if (win == curwin)
2449     {
2450 	curwin = wp;
2451 #ifdef FEAT_QUICKFIX
2452 	if (wp->w_p_pvw || bt_quickfix(wp->w_buffer))
2453 	{
2454 	    /*
2455 	     * If the cursor goes to the preview or the quickfix window, try
2456 	     * finding another window to go to.
2457 	     */
2458 	    for (;;)
2459 	    {
2460 		if (wp->w_next == NULL)
2461 		    wp = firstwin;
2462 		else
2463 		    wp = wp->w_next;
2464 		if (wp == curwin)
2465 		    break;
2466 		if (!wp->w_p_pvw && !bt_quickfix(wp->w_buffer))
2467 		{
2468 		    curwin = wp;
2469 		    break;
2470 		}
2471 	    }
2472 	}
2473 #endif
2474 	curbuf = curwin->w_buffer;
2475 	close_curwin = TRUE;
2476 
2477 	/* The cursor position may be invalid if the buffer changed after last
2478 	 * using the window. */
2479 	check_cursor();
2480     }
2481     if (p_ea && (*p_ead == 'b' || *p_ead == dir))
2482 	/* If the frame of the closed window contains the new current window,
2483 	 * only resize that frame.  Otherwise resize all windows. */
2484 	win_equal(curwin, curwin->w_frame->fr_parent == win_frame, dir);
2485     else
2486 	win_comp_pos();
2487     if (close_curwin)
2488     {
2489 	win_enter_ext(wp, FALSE, TRUE, FALSE, TRUE, TRUE);
2490 	if (other_buffer)
2491 	    /* careful: after this wp and win may be invalid! */
2492 	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
2493     }
2494 
2495     /*
2496      * If last window has a status line now and we don't want one,
2497      * remove the status line.
2498      */
2499     last_status(FALSE);
2500 
2501     /* After closing the help window, try restoring the window layout from
2502      * before it was opened. */
2503     if (help_window)
2504 	restore_snapshot(SNAP_HELP_IDX, close_curwin);
2505 
2506 #if defined(FEAT_GUI)
2507     /* When 'guioptions' includes 'L' or 'R' may have to remove scrollbars. */
2508     if (gui.in_use && !win_hasvertsplit())
2509 	gui_init_which_components(NULL);
2510 #endif
2511 
2512     redraw_all_later(NOT_VALID);
2513     return OK;
2514 }
2515 
2516 /*
2517  * Close window "win" in tab page "tp", which is not the current tab page.
2518  * This may be the last window in that tab page and result in closing the tab,
2519  * thus "tp" may become invalid!
2520  * Caller must check if buffer is hidden and whether the tabline needs to be
2521  * updated.
2522  */
2523     void
2524 win_close_othertab(win_T *win, int free_buf, tabpage_T *tp)
2525 {
2526     win_T	*wp;
2527     int		dir;
2528     tabpage_T   *ptp = NULL;
2529     int		free_tp = FALSE;
2530 
2531     /* Get here with win->w_buffer == NULL when win_close() detects the tab
2532      * page changed. */
2533     if (win->w_closing || (win->w_buffer != NULL
2534 					       && win->w_buffer->b_locked > 0))
2535 	return; /* window is already being closed */
2536 
2537     if (win->w_buffer != NULL)
2538 	/* Close the link to the buffer. */
2539 	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, FALSE);
2540 
2541     /* Careful: Autocommands may have closed the tab page or made it the
2542      * current tab page.  */
2543     for (ptp = first_tabpage; ptp != NULL && ptp != tp; ptp = ptp->tp_next)
2544 	;
2545     if (ptp == NULL || tp == curtab)
2546 	return;
2547 
2548     /* Autocommands may have closed the window already. */
2549     for (wp = tp->tp_firstwin; wp != NULL && wp != win; wp = wp->w_next)
2550 	;
2551     if (wp == NULL)
2552 	return;
2553 
2554     /* When closing the last window in a tab page remove the tab page. */
2555     if (tp->tp_firstwin == tp->tp_lastwin)
2556     {
2557 	if (tp == first_tabpage)
2558 	    first_tabpage = tp->tp_next;
2559 	else
2560 	{
2561 	    for (ptp = first_tabpage; ptp != NULL && ptp->tp_next != tp;
2562 							   ptp = ptp->tp_next)
2563 		;
2564 	    if (ptp == NULL)
2565 	    {
2566 		internal_error("win_close_othertab()");
2567 		return;
2568 	    }
2569 	    ptp->tp_next = tp->tp_next;
2570 	}
2571 	free_tp = TRUE;
2572     }
2573 
2574     /* Free the memory used for the window. */
2575     win_free_mem(win, &dir, tp);
2576 
2577     if (free_tp)
2578 	free_tabpage(tp);
2579 }
2580 
2581 /*
2582  * Free the memory used for a window.
2583  * Returns a pointer to the window that got the freed up space.
2584  */
2585     static win_T *
2586 win_free_mem(
2587     win_T	*win,
2588     int		*dirp,		/* set to 'v' or 'h' for direction if 'ea' */
2589     tabpage_T	*tp)		/* tab page "win" is in, NULL for current */
2590 {
2591     frame_T	*frp;
2592     win_T	*wp;
2593 
2594     /* Remove the window and its frame from the tree of frames. */
2595     frp = win->w_frame;
2596     wp = winframe_remove(win, dirp, tp);
2597     vim_free(frp);
2598     win_free(win, tp);
2599 
2600     /* When deleting the current window of another tab page select a new
2601      * current window. */
2602     if (tp != NULL && win == tp->tp_curwin)
2603 	tp->tp_curwin = wp;
2604 
2605     return wp;
2606 }
2607 
2608 #if defined(EXITFREE) || defined(PROTO)
2609     void
2610 win_free_all(void)
2611 {
2612     int		dummy;
2613 
2614     while (first_tabpage->tp_next != NULL)
2615 	tabpage_close(TRUE);
2616 
2617     if (aucmd_win != NULL)
2618     {
2619 	(void)win_free_mem(aucmd_win, &dummy, NULL);
2620 	aucmd_win = NULL;
2621     }
2622 
2623     while (firstwin != NULL)
2624 	(void)win_free_mem(firstwin, &dummy, NULL);
2625 
2626     /* No window should be used after this. Set curwin to NULL to crash
2627      * instead of using freed memory. */
2628     curwin = NULL;
2629 }
2630 #endif
2631 
2632 /*
2633  * Remove a window and its frame from the tree of frames.
2634  * Returns a pointer to the window that got the freed up space.
2635  */
2636     win_T *
2637 winframe_remove(
2638     win_T	*win,
2639     int		*dirp UNUSED,	/* set to 'v' or 'h' for direction if 'ea' */
2640     tabpage_T	*tp)		/* tab page "win" is in, NULL for current */
2641 {
2642     frame_T	*frp, *frp2, *frp3;
2643     frame_T	*frp_close = win->w_frame;
2644     win_T	*wp;
2645 
2646     /*
2647      * If there is only one window there is nothing to remove.
2648      */
2649     if (tp == NULL ? ONE_WINDOW : tp->tp_firstwin == tp->tp_lastwin)
2650 	return NULL;
2651 
2652     /*
2653      * Remove the window from its frame.
2654      */
2655     frp2 = win_altframe(win, tp);
2656     wp = frame2win(frp2);
2657 
2658     /* Remove this frame from the list of frames. */
2659     frame_remove(frp_close);
2660 
2661     if (frp_close->fr_parent->fr_layout == FR_COL)
2662     {
2663 	/* When 'winfixheight' is set, try to find another frame in the column
2664 	 * (as close to the closed frame as possible) to distribute the height
2665 	 * to. */
2666 	if (frp2->fr_win != NULL && frp2->fr_win->w_p_wfh)
2667 	{
2668 	    frp = frp_close->fr_prev;
2669 	    frp3 = frp_close->fr_next;
2670 	    while (frp != NULL || frp3 != NULL)
2671 	    {
2672 		if (frp != NULL)
2673 		{
2674 		    if (frp->fr_win != NULL && !frp->fr_win->w_p_wfh)
2675 		    {
2676 			frp2 = frp;
2677 			wp = frp->fr_win;
2678 			break;
2679 		    }
2680 		    frp = frp->fr_prev;
2681 		}
2682 		if (frp3 != NULL)
2683 		{
2684 		    if (frp3->fr_win != NULL && !frp3->fr_win->w_p_wfh)
2685 		    {
2686 			frp2 = frp3;
2687 			wp = frp3->fr_win;
2688 			break;
2689 		    }
2690 		    frp3 = frp3->fr_next;
2691 		}
2692 	    }
2693 	}
2694 	frame_new_height(frp2, frp2->fr_height + frp_close->fr_height,
2695 			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
2696 	*dirp = 'v';
2697     }
2698     else
2699     {
2700 	/* When 'winfixwidth' is set, try to find another frame in the column
2701 	 * (as close to the closed frame as possible) to distribute the width
2702 	 * to. */
2703 	if (frp2->fr_win != NULL && frp2->fr_win->w_p_wfw)
2704 	{
2705 	    frp = frp_close->fr_prev;
2706 	    frp3 = frp_close->fr_next;
2707 	    while (frp != NULL || frp3 != NULL)
2708 	    {
2709 		if (frp != NULL)
2710 		{
2711 		    if (frp->fr_win != NULL && !frp->fr_win->w_p_wfw)
2712 		    {
2713 			frp2 = frp;
2714 			wp = frp->fr_win;
2715 			break;
2716 		    }
2717 		    frp = frp->fr_prev;
2718 		}
2719 		if (frp3 != NULL)
2720 		{
2721 		    if (frp3->fr_win != NULL && !frp3->fr_win->w_p_wfw)
2722 		    {
2723 			frp2 = frp3;
2724 			wp = frp3->fr_win;
2725 			break;
2726 		    }
2727 		    frp3 = frp3->fr_next;
2728 		}
2729 	    }
2730 	}
2731 	frame_new_width(frp2, frp2->fr_width + frp_close->fr_width,
2732 			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
2733 	*dirp = 'h';
2734     }
2735 
2736     /* If rows/columns go to a window below/right its positions need to be
2737      * updated.  Can only be done after the sizes have been updated. */
2738     if (frp2 == frp_close->fr_next)
2739     {
2740 	int row = win->w_winrow;
2741 	int col = win->w_wincol;
2742 
2743 	frame_comp_pos(frp2, &row, &col);
2744     }
2745 
2746     if (frp2->fr_next == NULL && frp2->fr_prev == NULL)
2747     {
2748 	/* There is no other frame in this list, move its info to the parent
2749 	 * and remove it. */
2750 	frp2->fr_parent->fr_layout = frp2->fr_layout;
2751 	frp2->fr_parent->fr_child = frp2->fr_child;
2752 	FOR_ALL_FRAMES(frp, frp2->fr_child)
2753 	    frp->fr_parent = frp2->fr_parent;
2754 	frp2->fr_parent->fr_win = frp2->fr_win;
2755 	if (frp2->fr_win != NULL)
2756 	    frp2->fr_win->w_frame = frp2->fr_parent;
2757 	frp = frp2->fr_parent;
2758 	if (topframe->fr_child == frp2)
2759 	    topframe->fr_child = frp;
2760 	vim_free(frp2);
2761 
2762 	frp2 = frp->fr_parent;
2763 	if (frp2 != NULL && frp2->fr_layout == frp->fr_layout)
2764 	{
2765 	    /* The frame above the parent has the same layout, have to merge
2766 	     * the frames into this list. */
2767 	    if (frp2->fr_child == frp)
2768 		frp2->fr_child = frp->fr_child;
2769 	    frp->fr_child->fr_prev = frp->fr_prev;
2770 	    if (frp->fr_prev != NULL)
2771 		frp->fr_prev->fr_next = frp->fr_child;
2772 	    for (frp3 = frp->fr_child; ; frp3 = frp3->fr_next)
2773 	    {
2774 		frp3->fr_parent = frp2;
2775 		if (frp3->fr_next == NULL)
2776 		{
2777 		    frp3->fr_next = frp->fr_next;
2778 		    if (frp->fr_next != NULL)
2779 			frp->fr_next->fr_prev = frp3;
2780 		    break;
2781 		}
2782 	    }
2783 	    if (topframe->fr_child == frp)
2784 		topframe->fr_child = frp2;
2785 	    vim_free(frp);
2786 	}
2787     }
2788 
2789     return wp;
2790 }
2791 
2792 /*
2793  * Return a pointer to the frame that will receive the empty screen space that
2794  * is left over after "win" is closed.
2795  *
2796  * If 'splitbelow' or 'splitright' is set, the space goes above or to the left
2797  * by default.  Otherwise, the free space goes below or to the right.  The
2798  * result is that opening a window and then immediately closing it will
2799  * preserve the initial window layout.  The 'wfh' and 'wfw' settings are
2800  * respected when possible.
2801  */
2802     static frame_T *
2803 win_altframe(
2804     win_T	*win,
2805     tabpage_T	*tp)		/* tab page "win" is in, NULL for current */
2806 {
2807     frame_T	*frp;
2808     frame_T	*other_fr, *target_fr;
2809 
2810     if (tp == NULL ? ONE_WINDOW : tp->tp_firstwin == tp->tp_lastwin)
2811 	return alt_tabpage()->tp_curwin->w_frame;
2812 
2813     frp = win->w_frame;
2814 
2815     if (frp->fr_prev == NULL)
2816 	return frp->fr_next;
2817     if (frp->fr_next == NULL)
2818 	return frp->fr_prev;
2819 
2820     target_fr = frp->fr_next;
2821     other_fr  = frp->fr_prev;
2822     if (p_spr || p_sb)
2823     {
2824 	target_fr = frp->fr_prev;
2825 	other_fr  = frp->fr_next;
2826     }
2827 
2828     /* If 'wfh' or 'wfw' is set for the target and not for the alternate
2829      * window, reverse the selection. */
2830     if (frp->fr_parent != NULL && frp->fr_parent->fr_layout == FR_ROW)
2831     {
2832 	if (frame_fixed_width(target_fr) && !frame_fixed_width(other_fr))
2833 	    target_fr = other_fr;
2834     }
2835     else
2836     {
2837 	if (frame_fixed_height(target_fr) && !frame_fixed_height(other_fr))
2838 	    target_fr = other_fr;
2839     }
2840 
2841     return target_fr;
2842 }
2843 
2844 /*
2845  * Return the tabpage that will be used if the current one is closed.
2846  */
2847     static tabpage_T *
2848 alt_tabpage(void)
2849 {
2850     tabpage_T	*tp;
2851 
2852     /* Use the next tab page if possible. */
2853     if (curtab->tp_next != NULL)
2854 	return curtab->tp_next;
2855 
2856     /* Find the last but one tab page. */
2857     for (tp = first_tabpage; tp->tp_next != curtab; tp = tp->tp_next)
2858 	;
2859     return tp;
2860 }
2861 
2862 /*
2863  * Find the left-upper window in frame "frp".
2864  */
2865     static win_T *
2866 frame2win(frame_T *frp)
2867 {
2868     while (frp->fr_win == NULL)
2869 	frp = frp->fr_child;
2870     return frp->fr_win;
2871 }
2872 
2873 /*
2874  * Return TRUE if frame "frp" contains window "wp".
2875  */
2876     static int
2877 frame_has_win(frame_T *frp, win_T *wp)
2878 {
2879     frame_T	*p;
2880 
2881     if (frp->fr_layout == FR_LEAF)
2882 	return frp->fr_win == wp;
2883 
2884     FOR_ALL_FRAMES(p, frp->fr_child)
2885 	if (frame_has_win(p, wp))
2886 	    return TRUE;
2887     return FALSE;
2888 }
2889 
2890 /*
2891  * Set a new height for a frame.  Recursively sets the height for contained
2892  * frames and windows.  Caller must take care of positions.
2893  */
2894     static void
2895 frame_new_height(
2896     frame_T	*topfrp,
2897     int		height,
2898     int		topfirst,	/* resize topmost contained frame first */
2899     int		wfh)		/* obey 'winfixheight' when there is a choice;
2900 				   may cause the height not to be set */
2901 {
2902     frame_T	*frp;
2903     int		extra_lines;
2904     int		h;
2905 
2906     if (topfrp->fr_win != NULL)
2907     {
2908 	/* Simple case: just one window. */
2909 	win_new_height(topfrp->fr_win,
2910 				    height - topfrp->fr_win->w_status_height
2911 					      - WINBAR_HEIGHT(topfrp->fr_win));
2912     }
2913     else if (topfrp->fr_layout == FR_ROW)
2914     {
2915 	do
2916 	{
2917 	    /* All frames in this row get the same new height. */
2918 	    FOR_ALL_FRAMES(frp, topfrp->fr_child)
2919 	    {
2920 		frame_new_height(frp, height, topfirst, wfh);
2921 		if (frp->fr_height > height)
2922 		{
2923 		    /* Could not fit the windows, make the whole row higher. */
2924 		    height = frp->fr_height;
2925 		    break;
2926 		}
2927 	    }
2928 	}
2929 	while (frp != NULL);
2930     }
2931     else    /* fr_layout == FR_COL */
2932     {
2933 	/* Complicated case: Resize a column of frames.  Resize the bottom
2934 	 * frame first, frames above that when needed. */
2935 
2936 	frp = topfrp->fr_child;
2937 	if (wfh)
2938 	    /* Advance past frames with one window with 'wfh' set. */
2939 	    while (frame_fixed_height(frp))
2940 	    {
2941 		frp = frp->fr_next;
2942 		if (frp == NULL)
2943 		    return;	    /* no frame without 'wfh', give up */
2944 	    }
2945 	if (!topfirst)
2946 	{
2947 	    /* Find the bottom frame of this column */
2948 	    while (frp->fr_next != NULL)
2949 		frp = frp->fr_next;
2950 	    if (wfh)
2951 		/* Advance back for frames with one window with 'wfh' set. */
2952 		while (frame_fixed_height(frp))
2953 		    frp = frp->fr_prev;
2954 	}
2955 
2956 	extra_lines = height - topfrp->fr_height;
2957 	if (extra_lines < 0)
2958 	{
2959 	    /* reduce height of contained frames, bottom or top frame first */
2960 	    while (frp != NULL)
2961 	    {
2962 		h = frame_minheight(frp, NULL);
2963 		if (frp->fr_height + extra_lines < h)
2964 		{
2965 		    extra_lines += frp->fr_height - h;
2966 		    frame_new_height(frp, h, topfirst, wfh);
2967 		}
2968 		else
2969 		{
2970 		    frame_new_height(frp, frp->fr_height + extra_lines,
2971 							       topfirst, wfh);
2972 		    break;
2973 		}
2974 		if (topfirst)
2975 		{
2976 		    do
2977 			frp = frp->fr_next;
2978 		    while (wfh && frp != NULL && frame_fixed_height(frp));
2979 		}
2980 		else
2981 		{
2982 		    do
2983 			frp = frp->fr_prev;
2984 		    while (wfh && frp != NULL && frame_fixed_height(frp));
2985 		}
2986 		/* Increase "height" if we could not reduce enough frames. */
2987 		if (frp == NULL)
2988 		    height -= extra_lines;
2989 	    }
2990 	}
2991 	else if (extra_lines > 0)
2992 	{
2993 	    /* increase height of bottom or top frame */
2994 	    frame_new_height(frp, frp->fr_height + extra_lines, topfirst, wfh);
2995 	}
2996     }
2997     topfrp->fr_height = height;
2998 }
2999 
3000 /*
3001  * Return TRUE if height of frame "frp" should not be changed because of
3002  * the 'winfixheight' option.
3003  */
3004     static int
3005 frame_fixed_height(frame_T *frp)
3006 {
3007     /* frame with one window: fixed height if 'winfixheight' set. */
3008     if (frp->fr_win != NULL)
3009 	return frp->fr_win->w_p_wfh;
3010 
3011     if (frp->fr_layout == FR_ROW)
3012     {
3013 	/* The frame is fixed height if one of the frames in the row is fixed
3014 	 * height. */
3015 	FOR_ALL_FRAMES(frp, frp->fr_child)
3016 	    if (frame_fixed_height(frp))
3017 		return TRUE;
3018 	return FALSE;
3019     }
3020 
3021     /* frp->fr_layout == FR_COL: The frame is fixed height if all of the
3022      * frames in the row are fixed height. */
3023     FOR_ALL_FRAMES(frp, frp->fr_child)
3024 	if (!frame_fixed_height(frp))
3025 	    return FALSE;
3026     return TRUE;
3027 }
3028 
3029 /*
3030  * Return TRUE if width of frame "frp" should not be changed because of
3031  * the 'winfixwidth' option.
3032  */
3033     static int
3034 frame_fixed_width(frame_T *frp)
3035 {
3036     /* frame with one window: fixed width if 'winfixwidth' set. */
3037     if (frp->fr_win != NULL)
3038 	return frp->fr_win->w_p_wfw;
3039 
3040     if (frp->fr_layout == FR_COL)
3041     {
3042 	/* The frame is fixed width if one of the frames in the row is fixed
3043 	 * width. */
3044 	FOR_ALL_FRAMES(frp, frp->fr_child)
3045 	    if (frame_fixed_width(frp))
3046 		return TRUE;
3047 	return FALSE;
3048     }
3049 
3050     /* frp->fr_layout == FR_ROW: The frame is fixed width if all of the
3051      * frames in the row are fixed width. */
3052     FOR_ALL_FRAMES(frp, frp->fr_child)
3053 	if (!frame_fixed_width(frp))
3054 	    return FALSE;
3055     return TRUE;
3056 }
3057 
3058 /*
3059  * Add a status line to windows at the bottom of "frp".
3060  * Note: Does not check if there is room!
3061  */
3062     static void
3063 frame_add_statusline(frame_T *frp)
3064 {
3065     win_T	*wp;
3066 
3067     if (frp->fr_layout == FR_LEAF)
3068     {
3069 	wp = frp->fr_win;
3070 	if (wp->w_status_height == 0)
3071 	{
3072 	    if (wp->w_height > 0)	/* don't make it negative */
3073 		--wp->w_height;
3074 	    wp->w_status_height = STATUS_HEIGHT;
3075 	}
3076     }
3077     else if (frp->fr_layout == FR_ROW)
3078     {
3079 	/* Handle all the frames in the row. */
3080 	FOR_ALL_FRAMES(frp, frp->fr_child)
3081 	    frame_add_statusline(frp);
3082     }
3083     else /* frp->fr_layout == FR_COL */
3084     {
3085 	/* Only need to handle the last frame in the column. */
3086 	for (frp = frp->fr_child; frp->fr_next != NULL; frp = frp->fr_next)
3087 	    ;
3088 	frame_add_statusline(frp);
3089     }
3090 }
3091 
3092 /*
3093  * Set width of a frame.  Handles recursively going through contained frames.
3094  * May remove separator line for windows at the right side (for win_close()).
3095  */
3096     static void
3097 frame_new_width(
3098     frame_T	*topfrp,
3099     int		width,
3100     int		leftfirst,	/* resize leftmost contained frame first */
3101     int		wfw)		/* obey 'winfixwidth' when there is a choice;
3102 				   may cause the width not to be set */
3103 {
3104     frame_T	*frp;
3105     int		extra_cols;
3106     int		w;
3107     win_T	*wp;
3108 
3109     if (topfrp->fr_layout == FR_LEAF)
3110     {
3111 	/* Simple case: just one window. */
3112 	wp = topfrp->fr_win;
3113 	/* Find out if there are any windows right of this one. */
3114 	for (frp = topfrp; frp->fr_parent != NULL; frp = frp->fr_parent)
3115 	    if (frp->fr_parent->fr_layout == FR_ROW && frp->fr_next != NULL)
3116 		break;
3117 	if (frp->fr_parent == NULL)
3118 	    wp->w_vsep_width = 0;
3119 	win_new_width(wp, width - wp->w_vsep_width);
3120     }
3121     else if (topfrp->fr_layout == FR_COL)
3122     {
3123 	do
3124 	{
3125 	    /* All frames in this column get the same new width. */
3126 	    FOR_ALL_FRAMES(frp, topfrp->fr_child)
3127 	    {
3128 		frame_new_width(frp, width, leftfirst, wfw);
3129 		if (frp->fr_width > width)
3130 		{
3131 		    /* Could not fit the windows, make whole column wider. */
3132 		    width = frp->fr_width;
3133 		    break;
3134 		}
3135 	    }
3136 	} while (frp != NULL);
3137     }
3138     else    /* fr_layout == FR_ROW */
3139     {
3140 	/* Complicated case: Resize a row of frames.  Resize the rightmost
3141 	 * frame first, frames left of it when needed. */
3142 
3143 	frp = topfrp->fr_child;
3144 	if (wfw)
3145 	    /* Advance past frames with one window with 'wfw' set. */
3146 	    while (frame_fixed_width(frp))
3147 	    {
3148 		frp = frp->fr_next;
3149 		if (frp == NULL)
3150 		    return;	    /* no frame without 'wfw', give up */
3151 	    }
3152 	if (!leftfirst)
3153 	{
3154 	    /* Find the rightmost frame of this row */
3155 	    while (frp->fr_next != NULL)
3156 		frp = frp->fr_next;
3157 	    if (wfw)
3158 		/* Advance back for frames with one window with 'wfw' set. */
3159 		while (frame_fixed_width(frp))
3160 		    frp = frp->fr_prev;
3161 	}
3162 
3163 	extra_cols = width - topfrp->fr_width;
3164 	if (extra_cols < 0)
3165 	{
3166 	    /* reduce frame width, rightmost frame first */
3167 	    while (frp != NULL)
3168 	    {
3169 		w = frame_minwidth(frp, NULL);
3170 		if (frp->fr_width + extra_cols < w)
3171 		{
3172 		    extra_cols += frp->fr_width - w;
3173 		    frame_new_width(frp, w, leftfirst, wfw);
3174 		}
3175 		else
3176 		{
3177 		    frame_new_width(frp, frp->fr_width + extra_cols,
3178 							      leftfirst, wfw);
3179 		    break;
3180 		}
3181 		if (leftfirst)
3182 		{
3183 		    do
3184 			frp = frp->fr_next;
3185 		    while (wfw && frp != NULL && frame_fixed_width(frp));
3186 		}
3187 		else
3188 		{
3189 		    do
3190 			frp = frp->fr_prev;
3191 		    while (wfw && frp != NULL && frame_fixed_width(frp));
3192 		}
3193 		/* Increase "width" if we could not reduce enough frames. */
3194 		if (frp == NULL)
3195 		    width -= extra_cols;
3196 	    }
3197 	}
3198 	else if (extra_cols > 0)
3199 	{
3200 	    /* increase width of rightmost frame */
3201 	    frame_new_width(frp, frp->fr_width + extra_cols, leftfirst, wfw);
3202 	}
3203     }
3204     topfrp->fr_width = width;
3205 }
3206 
3207 /*
3208  * Add the vertical separator to windows at the right side of "frp".
3209  * Note: Does not check if there is room!
3210  */
3211     static void
3212 frame_add_vsep(frame_T *frp)
3213 {
3214     win_T	*wp;
3215 
3216     if (frp->fr_layout == FR_LEAF)
3217     {
3218 	wp = frp->fr_win;
3219 	if (wp->w_vsep_width == 0)
3220 	{
3221 	    if (wp->w_width > 0)	/* don't make it negative */
3222 		--wp->w_width;
3223 	    wp->w_vsep_width = 1;
3224 	}
3225     }
3226     else if (frp->fr_layout == FR_COL)
3227     {
3228 	/* Handle all the frames in the column. */
3229 	FOR_ALL_FRAMES(frp, frp->fr_child)
3230 	    frame_add_vsep(frp);
3231     }
3232     else /* frp->fr_layout == FR_ROW */
3233     {
3234 	/* Only need to handle the last frame in the row. */
3235 	frp = frp->fr_child;
3236 	while (frp->fr_next != NULL)
3237 	    frp = frp->fr_next;
3238 	frame_add_vsep(frp);
3239     }
3240 }
3241 
3242 /*
3243  * Set frame width from the window it contains.
3244  */
3245     static void
3246 frame_fix_width(win_T *wp)
3247 {
3248     wp->w_frame->fr_width = wp->w_width + wp->w_vsep_width;
3249 }
3250 
3251 /*
3252  * Set frame height from the window it contains.
3253  */
3254     static void
3255 frame_fix_height(win_T *wp)
3256 {
3257     wp->w_frame->fr_height = VISIBLE_HEIGHT(wp) + wp->w_status_height;
3258 }
3259 
3260 /*
3261  * Compute the minimal height for frame "topfrp".
3262  * Uses the 'winminheight' option.
3263  * When "next_curwin" isn't NULL, use p_wh for this window.
3264  * When "next_curwin" is NOWIN, don't use at least one line for the current
3265  * window.
3266  */
3267     static int
3268 frame_minheight(frame_T *topfrp, win_T *next_curwin)
3269 {
3270     frame_T	*frp;
3271     int		m;
3272     int		n;
3273 
3274     if (topfrp->fr_win != NULL)
3275     {
3276 	if (topfrp->fr_win == next_curwin)
3277 	    m = p_wh + topfrp->fr_win->w_status_height;
3278 	else
3279 	{
3280 	    /* window: minimal height of the window plus status line */
3281 	    m = p_wmh + topfrp->fr_win->w_status_height;
3282 	    if (topfrp->fr_win == curwin && next_curwin == NULL)
3283 	    {
3284 		/* Current window is minimal one line high and WinBar is
3285 		 * visible. */
3286 		if (p_wmh == 0)
3287 		    ++m;
3288 		m += WINBAR_HEIGHT(curwin);
3289 	    }
3290 	}
3291     }
3292     else if (topfrp->fr_layout == FR_ROW)
3293     {
3294 	/* get the minimal height from each frame in this row */
3295 	m = 0;
3296 	FOR_ALL_FRAMES(frp, topfrp->fr_child)
3297 	{
3298 	    n = frame_minheight(frp, next_curwin);
3299 	    if (n > m)
3300 		m = n;
3301 	}
3302     }
3303     else
3304     {
3305 	/* Add up the minimal heights for all frames in this column. */
3306 	m = 0;
3307 	FOR_ALL_FRAMES(frp, topfrp->fr_child)
3308 	    m += frame_minheight(frp, next_curwin);
3309     }
3310 
3311     return m;
3312 }
3313 
3314 /*
3315  * Compute the minimal width for frame "topfrp".
3316  * When "next_curwin" isn't NULL, use p_wiw for this window.
3317  * When "next_curwin" is NOWIN, don't use at least one column for the current
3318  * window.
3319  */
3320     static int
3321 frame_minwidth(
3322     frame_T	*topfrp,
3323     win_T	*next_curwin)	/* use p_wh and p_wiw for next_curwin */
3324 {
3325     frame_T	*frp;
3326     int		m, n;
3327 
3328     if (topfrp->fr_win != NULL)
3329     {
3330 	if (topfrp->fr_win == next_curwin)
3331 	    m = p_wiw + topfrp->fr_win->w_vsep_width;
3332 	else
3333 	{
3334 	    /* window: minimal width of the window plus separator column */
3335 	    m = p_wmw + topfrp->fr_win->w_vsep_width;
3336 	    /* Current window is minimal one column wide */
3337 	    if (p_wmw == 0 && topfrp->fr_win == curwin && next_curwin == NULL)
3338 		++m;
3339 	}
3340     }
3341     else if (topfrp->fr_layout == FR_COL)
3342     {
3343 	/* get the minimal width from each frame in this column */
3344 	m = 0;
3345 	FOR_ALL_FRAMES(frp, topfrp->fr_child)
3346 	{
3347 	    n = frame_minwidth(frp, next_curwin);
3348 	    if (n > m)
3349 		m = n;
3350 	}
3351     }
3352     else
3353     {
3354 	/* Add up the minimal widths for all frames in this row. */
3355 	m = 0;
3356 	FOR_ALL_FRAMES(frp, topfrp->fr_child)
3357 	    m += frame_minwidth(frp, next_curwin);
3358     }
3359 
3360     return m;
3361 }
3362 
3363 
3364 /*
3365  * Try to close all windows except current one.
3366  * Buffers in the other windows become hidden if 'hidden' is set, or '!' is
3367  * used and the buffer was modified.
3368  *
3369  * Used by ":bdel" and ":only".
3370  */
3371     void
3372 close_others(
3373     int		message,
3374     int		forceit)	    /* always hide all other windows */
3375 {
3376     win_T	*wp;
3377     win_T	*nextwp;
3378     int		r;
3379 
3380     if (one_window())
3381     {
3382 	if (message && !autocmd_busy)
3383 	    msg(_(m_onlyone));
3384 	return;
3385     }
3386 
3387     /* Be very careful here: autocommands may change the window layout. */
3388     for (wp = firstwin; win_valid(wp); wp = nextwp)
3389     {
3390 	nextwp = wp->w_next;
3391 	if (wp != curwin)		/* don't close current window */
3392 	{
3393 
3394 	    /* Check if it's allowed to abandon this window */
3395 	    r = can_abandon(wp->w_buffer, forceit);
3396 	    if (!win_valid(wp))		/* autocommands messed wp up */
3397 	    {
3398 		nextwp = firstwin;
3399 		continue;
3400 	    }
3401 	    if (!r)
3402 	    {
3403 #if defined(FEAT_GUI_DIALOG) || defined(FEAT_CON_DIALOG)
3404 		if (message && (p_confirm || cmdmod.confirm) && p_write)
3405 		{
3406 		    dialog_changed(wp->w_buffer, FALSE);
3407 		    if (!win_valid(wp))		/* autocommands messed wp up */
3408 		    {
3409 			nextwp = firstwin;
3410 			continue;
3411 		    }
3412 		}
3413 		if (bufIsChanged(wp->w_buffer))
3414 #endif
3415 		    continue;
3416 	    }
3417 	    win_close(wp, !buf_hide(wp->w_buffer)
3418 					       && !bufIsChanged(wp->w_buffer));
3419 	}
3420     }
3421 
3422     if (message && !ONE_WINDOW)
3423 	emsg(_("E445: Other window contains changes"));
3424 }
3425 
3426 /*
3427  * Init the current window "curwin".
3428  * Called when a new file is being edited.
3429  */
3430     void
3431 curwin_init(void)
3432 {
3433     win_init_empty(curwin);
3434 }
3435 
3436     void
3437 win_init_empty(win_T *wp)
3438 {
3439     redraw_win_later(wp, NOT_VALID);
3440     wp->w_lines_valid = 0;
3441     wp->w_cursor.lnum = 1;
3442     wp->w_curswant = wp->w_cursor.col = 0;
3443     wp->w_cursor.coladd = 0;
3444     wp->w_pcmark.lnum = 1;	/* pcmark not cleared but set to line 1 */
3445     wp->w_pcmark.col = 0;
3446     wp->w_prev_pcmark.lnum = 0;
3447     wp->w_prev_pcmark.col = 0;
3448     wp->w_topline = 1;
3449 #ifdef FEAT_DIFF
3450     wp->w_topfill = 0;
3451 #endif
3452     wp->w_botline = 2;
3453 #ifdef FEAT_SYN_HL
3454     wp->w_s = &wp->w_buffer->b_s;
3455 #endif
3456 }
3457 
3458 /*
3459  * Allocate the first window and put an empty buffer in it.
3460  * Called from main().
3461  * Return FAIL when something goes wrong (out of memory).
3462  */
3463     int
3464 win_alloc_first(void)
3465 {
3466     if (win_alloc_firstwin(NULL) == FAIL)
3467 	return FAIL;
3468 
3469     first_tabpage = alloc_tabpage();
3470     if (first_tabpage == NULL)
3471 	return FAIL;
3472     first_tabpage->tp_topframe = topframe;
3473     curtab = first_tabpage;
3474 
3475     return OK;
3476 }
3477 
3478 /*
3479  * Init "aucmd_win".  This can only be done after the first
3480  * window is fully initialized, thus it can't be in win_alloc_first().
3481  */
3482     void
3483 win_alloc_aucmd_win(void)
3484 {
3485     aucmd_win = win_alloc(NULL, TRUE);
3486     if (aucmd_win != NULL)
3487     {
3488 	win_init_some(aucmd_win, curwin);
3489 	RESET_BINDING(aucmd_win);
3490 	new_frame(aucmd_win);
3491     }
3492 }
3493 
3494 /*
3495  * Allocate the first window or the first window in a new tab page.
3496  * When "oldwin" is NULL create an empty buffer for it.
3497  * When "oldwin" is not NULL copy info from it to the new window.
3498  * Return FAIL when something goes wrong (out of memory).
3499  */
3500     static int
3501 win_alloc_firstwin(win_T *oldwin)
3502 {
3503     curwin = win_alloc(NULL, FALSE);
3504     if (oldwin == NULL)
3505     {
3506 	/* Very first window, need to create an empty buffer for it and
3507 	 * initialize from scratch. */
3508 	curbuf = buflist_new(NULL, NULL, 1L, BLN_LISTED);
3509 	if (curwin == NULL || curbuf == NULL)
3510 	    return FAIL;
3511 	curwin->w_buffer = curbuf;
3512 #ifdef FEAT_SYN_HL
3513 	curwin->w_s = &(curbuf->b_s);
3514 #endif
3515 	curbuf->b_nwindows = 1;	/* there is one window */
3516 	curwin->w_alist = &global_alist;
3517 	curwin_init();		/* init current window */
3518     }
3519     else
3520     {
3521 	/* First window in new tab page, initialize it from "oldwin". */
3522 	win_init(curwin, oldwin, 0);
3523 
3524 	/* We don't want cursor- and scroll-binding in the first window. */
3525 	RESET_BINDING(curwin);
3526     }
3527 
3528     new_frame(curwin);
3529     if (curwin->w_frame == NULL)
3530 	return FAIL;
3531     topframe = curwin->w_frame;
3532     topframe->fr_width = Columns;
3533     topframe->fr_height = Rows - p_ch;
3534 
3535     return OK;
3536 }
3537 
3538 /*
3539  * Create a frame for window "wp".
3540  */
3541     static void
3542 new_frame(win_T *wp)
3543 {
3544     frame_T *frp = (frame_T *)alloc_clear((unsigned)sizeof(frame_T));
3545 
3546     wp->w_frame = frp;
3547     if (frp != NULL)
3548     {
3549 	frp->fr_layout = FR_LEAF;
3550 	frp->fr_win = wp;
3551     }
3552 }
3553 
3554 /*
3555  * Initialize the window and frame size to the maximum.
3556  */
3557     void
3558 win_init_size(void)
3559 {
3560     firstwin->w_height = ROWS_AVAIL;
3561     topframe->fr_height = ROWS_AVAIL;
3562     firstwin->w_width = Columns;
3563     topframe->fr_width = Columns;
3564 }
3565 
3566 /*
3567  * Allocate a new tabpage_T and init the values.
3568  * Returns NULL when out of memory.
3569  */
3570     static tabpage_T *
3571 alloc_tabpage(void)
3572 {
3573     tabpage_T	*tp;
3574 # ifdef FEAT_GUI
3575     int		i;
3576 # endif
3577 
3578 
3579     tp = (tabpage_T *)alloc_clear((unsigned)sizeof(tabpage_T));
3580     if (tp == NULL)
3581 	return NULL;
3582 
3583 # ifdef FEAT_EVAL
3584     /* init t: variables */
3585     tp->tp_vars = dict_alloc();
3586     if (tp->tp_vars == NULL)
3587     {
3588 	vim_free(tp);
3589 	return NULL;
3590     }
3591     init_var_dict(tp->tp_vars, &tp->tp_winvar, VAR_SCOPE);
3592 # endif
3593 
3594 # ifdef FEAT_GUI
3595     for (i = 0; i < 3; i++)
3596 	tp->tp_prev_which_scrollbars[i] = -1;
3597 # endif
3598 # ifdef FEAT_DIFF
3599     tp->tp_diff_invalid = TRUE;
3600 # endif
3601     tp->tp_ch_used = p_ch;
3602 
3603     return tp;
3604 }
3605 
3606     void
3607 free_tabpage(tabpage_T *tp)
3608 {
3609     int idx;
3610 
3611 # ifdef FEAT_DIFF
3612     diff_clear(tp);
3613 # endif
3614     for (idx = 0; idx < SNAP_COUNT; ++idx)
3615 	clear_snapshot(tp, idx);
3616 #ifdef FEAT_EVAL
3617     vars_clear(&tp->tp_vars->dv_hashtab);	/* free all t: variables */
3618     hash_init(&tp->tp_vars->dv_hashtab);
3619     unref_var_dict(tp->tp_vars);
3620 #endif
3621 
3622 #ifdef FEAT_PYTHON
3623     python_tabpage_free(tp);
3624 #endif
3625 
3626 #ifdef FEAT_PYTHON3
3627     python3_tabpage_free(tp);
3628 #endif
3629 
3630     vim_free(tp);
3631 }
3632 
3633 /*
3634  * Create a new Tab page with one window.
3635  * It will edit the current buffer, like after ":split".
3636  * When "after" is 0 put it just after the current Tab page.
3637  * Otherwise put it just before tab page "after".
3638  * Return FAIL or OK.
3639  */
3640     int
3641 win_new_tabpage(int after)
3642 {
3643     tabpage_T	*tp = curtab;
3644     tabpage_T	*newtp;
3645     int		n;
3646 
3647     newtp = alloc_tabpage();
3648     if (newtp == NULL)
3649 	return FAIL;
3650 
3651     /* Remember the current windows in this Tab page. */
3652     if (leave_tabpage(curbuf, TRUE) == FAIL)
3653     {
3654 	vim_free(newtp);
3655 	return FAIL;
3656     }
3657     curtab = newtp;
3658 
3659     /* Create a new empty window. */
3660     if (win_alloc_firstwin(tp->tp_curwin) == OK)
3661     {
3662 	/* Make the new Tab page the new topframe. */
3663 	if (after == 1)
3664 	{
3665 	    /* New tab page becomes the first one. */
3666 	    newtp->tp_next = first_tabpage;
3667 	    first_tabpage = newtp;
3668 	}
3669 	else
3670 	{
3671 	    if (after > 0)
3672 	    {
3673 		/* Put new tab page before tab page "after". */
3674 		n = 2;
3675 		for (tp = first_tabpage; tp->tp_next != NULL
3676 					       && n < after; tp = tp->tp_next)
3677 		    ++n;
3678 	    }
3679 	    newtp->tp_next = tp->tp_next;
3680 	    tp->tp_next = newtp;
3681 	}
3682 	win_init_size();
3683 	firstwin->w_winrow = tabline_height();
3684 	win_comp_scroll(curwin);
3685 
3686 	newtp->tp_topframe = topframe;
3687 	last_status(FALSE);
3688 
3689 #if defined(FEAT_GUI)
3690 	/* When 'guioptions' includes 'L' or 'R' may have to remove or add
3691 	 * scrollbars.  Have to update them anyway. */
3692 	gui_may_update_scrollbars();
3693 #endif
3694 #ifdef FEAT_JOB_CHANNEL
3695 	entering_window(curwin);
3696 #endif
3697 
3698 	redraw_all_later(NOT_VALID);
3699 	apply_autocmds(EVENT_WINNEW, NULL, NULL, FALSE, curbuf);
3700 	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
3701 	apply_autocmds(EVENT_TABNEW, NULL, NULL, FALSE, curbuf);
3702 	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
3703 	return OK;
3704     }
3705 
3706     /* Failed, get back the previous Tab page */
3707     enter_tabpage(curtab, curbuf, TRUE, TRUE);
3708     return FAIL;
3709 }
3710 
3711 /*
3712  * Open a new tab page if ":tab cmd" was used.  It will edit the same buffer,
3713  * like with ":split".
3714  * Returns OK if a new tab page was created, FAIL otherwise.
3715  */
3716     int
3717 may_open_tabpage(void)
3718 {
3719     int		n = (cmdmod.tab == 0) ? postponed_split_tab : cmdmod.tab;
3720 
3721     if (n != 0)
3722     {
3723 	cmdmod.tab = 0;	    /* reset it to avoid doing it twice */
3724 	postponed_split_tab = 0;
3725 	return win_new_tabpage(n);
3726     }
3727     return FAIL;
3728 }
3729 
3730 /*
3731  * Create up to "maxcount" tabpages with empty windows.
3732  * Returns the number of resulting tab pages.
3733  */
3734     int
3735 make_tabpages(int maxcount)
3736 {
3737     int		count = maxcount;
3738     int		todo;
3739 
3740     /* Limit to 'tabpagemax' tabs. */
3741     if (count > p_tpm)
3742 	count = p_tpm;
3743 
3744     /*
3745      * Don't execute autocommands while creating the tab pages.  Must do that
3746      * when putting the buffers in the windows.
3747      */
3748     block_autocmds();
3749 
3750     for (todo = count - 1; todo > 0; --todo)
3751 	if (win_new_tabpage(0) == FAIL)
3752 	    break;
3753 
3754     unblock_autocmds();
3755 
3756     /* return actual number of tab pages */
3757     return (count - todo);
3758 }
3759 
3760 /*
3761  * Return TRUE when "tpc" points to a valid tab page.
3762  */
3763     int
3764 valid_tabpage(tabpage_T *tpc)
3765 {
3766     tabpage_T	*tp;
3767 
3768     FOR_ALL_TABPAGES(tp)
3769 	if (tp == tpc)
3770 	    return TRUE;
3771     return FALSE;
3772 }
3773 
3774 /*
3775  * Return TRUE when "tpc" points to a valid tab page and at least one window is
3776  * valid.
3777  */
3778     int
3779 valid_tabpage_win(tabpage_T *tpc)
3780 {
3781     tabpage_T	*tp;
3782     win_T	*wp;
3783 
3784     FOR_ALL_TABPAGES(tp)
3785     {
3786 	if (tp == tpc)
3787 	{
3788 	    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
3789 	    {
3790 		if (win_valid_any_tab(wp))
3791 		    return TRUE;
3792 	    }
3793 	    return FALSE;
3794 	}
3795     }
3796     /* shouldn't happen */
3797     return FALSE;
3798 }
3799 
3800 /*
3801  * Close tabpage "tab", assuming it has no windows in it.
3802  * There must be another tabpage or this will crash.
3803  */
3804     void
3805 close_tabpage(tabpage_T *tab)
3806 {
3807     tabpage_T	*ptp;
3808 
3809     if (tab == first_tabpage)
3810     {
3811 	first_tabpage = tab->tp_next;
3812 	ptp = first_tabpage;
3813     }
3814     else
3815     {
3816 	for (ptp = first_tabpage; ptp != NULL && ptp->tp_next != tab;
3817 							    ptp = ptp->tp_next)
3818 	    ;
3819 	assert(ptp != NULL);
3820 	ptp->tp_next = tab->tp_next;
3821     }
3822 
3823     goto_tabpage_tp(ptp, FALSE, FALSE);
3824     free_tabpage(tab);
3825 }
3826 
3827 /*
3828  * Find tab page "n" (first one is 1).  Returns NULL when not found.
3829  */
3830     tabpage_T *
3831 find_tabpage(int n)
3832 {
3833     tabpage_T	*tp;
3834     int		i = 1;
3835 
3836     for (tp = first_tabpage; tp != NULL && i != n; tp = tp->tp_next)
3837 	++i;
3838     return tp;
3839 }
3840 
3841 /*
3842  * Get index of tab page "tp".  First one has index 1.
3843  * When not found returns number of tab pages plus one.
3844  */
3845     int
3846 tabpage_index(tabpage_T *ftp)
3847 {
3848     int		i = 1;
3849     tabpage_T	*tp;
3850 
3851     for (tp = first_tabpage; tp != NULL && tp != ftp; tp = tp->tp_next)
3852 	++i;
3853     return i;
3854 }
3855 
3856 /*
3857  * Prepare for leaving the current tab page.
3858  * When autocommands change "curtab" we don't leave the tab page and return
3859  * FAIL.
3860  * Careful: When OK is returned need to get a new tab page very very soon!
3861  */
3862     static int
3863 leave_tabpage(
3864     buf_T	*new_curbuf UNUSED,    /* what is going to be the new curbuf,
3865 				       NULL if unknown */
3866     int		trigger_leave_autocmds UNUSED)
3867 {
3868     tabpage_T	*tp = curtab;
3869 
3870 #ifdef FEAT_JOB_CHANNEL
3871     leaving_window(curwin);
3872 #endif
3873     reset_VIsual_and_resel();	/* stop Visual mode */
3874     if (trigger_leave_autocmds)
3875     {
3876 	if (new_curbuf != curbuf)
3877 	{
3878 	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
3879 	    if (curtab != tp)
3880 		return FAIL;
3881 	}
3882 	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
3883 	if (curtab != tp)
3884 	    return FAIL;
3885 	apply_autocmds(EVENT_TABLEAVE, NULL, NULL, FALSE, curbuf);
3886 	if (curtab != tp)
3887 	    return FAIL;
3888     }
3889 #if defined(FEAT_GUI)
3890     /* Remove the scrollbars.  They may be added back later. */
3891     if (gui.in_use)
3892 	gui_remove_scrollbars();
3893 #endif
3894     tp->tp_curwin = curwin;
3895     tp->tp_prevwin = prevwin;
3896     tp->tp_firstwin = firstwin;
3897     tp->tp_lastwin = lastwin;
3898     tp->tp_old_Rows = Rows;
3899     tp->tp_old_Columns = Columns;
3900     firstwin = NULL;
3901     lastwin = NULL;
3902     return OK;
3903 }
3904 
3905 /*
3906  * Start using tab page "tp".
3907  * Only to be used after leave_tabpage() or freeing the current tab page.
3908  * Only trigger *Enter autocommands when trigger_enter_autocmds is TRUE.
3909  * Only trigger *Leave autocommands when trigger_leave_autocmds is TRUE.
3910  */
3911     static void
3912 enter_tabpage(
3913     tabpage_T	*tp,
3914     buf_T	*old_curbuf UNUSED,
3915     int		trigger_enter_autocmds,
3916     int		trigger_leave_autocmds)
3917 {
3918     int		old_off = tp->tp_firstwin->w_winrow;
3919     win_T	*next_prevwin = tp->tp_prevwin;
3920 
3921     curtab = tp;
3922     firstwin = tp->tp_firstwin;
3923     lastwin = tp->tp_lastwin;
3924     topframe = tp->tp_topframe;
3925 
3926     /* We would like doing the TabEnter event first, but we don't have a
3927      * valid current window yet, which may break some commands.
3928      * This triggers autocommands, thus may make "tp" invalid. */
3929     win_enter_ext(tp->tp_curwin, FALSE, TRUE, FALSE,
3930 			      trigger_enter_autocmds, trigger_leave_autocmds);
3931     prevwin = next_prevwin;
3932 
3933     last_status(FALSE);		/* status line may appear or disappear */
3934     (void)win_comp_pos();	/* recompute w_winrow for all windows */
3935 #ifdef FEAT_DIFF
3936     diff_need_scrollbind = TRUE;
3937 #endif
3938 
3939     /* The tabpage line may have appeared or disappeared, may need to resize
3940      * the frames for that.  When the Vim window was resized need to update
3941      * frame sizes too.  Use the stored value of p_ch, so that it can be
3942      * different for each tab page. */
3943     p_ch = curtab->tp_ch_used;
3944     if (curtab->tp_old_Rows != Rows || (old_off != firstwin->w_winrow
3945 #ifdef FEAT_GUI_TABLINE
3946 			    && !gui_use_tabline()
3947 #endif
3948 		))
3949 	shell_new_rows();
3950     if (curtab->tp_old_Columns != Columns && starting == 0)
3951 	shell_new_columns();	/* update window widths */
3952 
3953 #if defined(FEAT_GUI)
3954     /* When 'guioptions' includes 'L' or 'R' may have to remove or add
3955      * scrollbars.  Have to update them anyway. */
3956     gui_may_update_scrollbars();
3957 #endif
3958 
3959     /* Apply autocommands after updating the display, when 'rows' and
3960      * 'columns' have been set correctly. */
3961     if (trigger_enter_autocmds)
3962     {
3963 	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
3964 	if (old_curbuf != curbuf)
3965 	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
3966     }
3967 
3968     redraw_all_later(NOT_VALID);
3969 }
3970 
3971 /*
3972  * Go to tab page "n".  For ":tab N" and "Ngt".
3973  * When "n" is 9999 go to the last tab page.
3974  */
3975     void
3976 goto_tabpage(int n)
3977 {
3978     tabpage_T	*tp;
3979     tabpage_T	*ttp;
3980     int		i;
3981 
3982     if (text_locked())
3983     {
3984 	/* Not allowed when editing the command line. */
3985 	text_locked_msg();
3986 	return;
3987     }
3988 
3989     /* If there is only one it can't work. */
3990     if (first_tabpage->tp_next == NULL)
3991     {
3992 	if (n > 1)
3993 	    beep_flush();
3994 	return;
3995     }
3996 
3997     if (n == 0)
3998     {
3999 	/* No count, go to next tab page, wrap around end. */
4000 	if (curtab->tp_next == NULL)
4001 	    tp = first_tabpage;
4002 	else
4003 	    tp = curtab->tp_next;
4004     }
4005     else if (n < 0)
4006     {
4007 	/* "gT": go to previous tab page, wrap around end.  "N gT" repeats
4008 	 * this N times. */
4009 	ttp = curtab;
4010 	for (i = n; i < 0; ++i)
4011 	{
4012 	    for (tp = first_tabpage; tp->tp_next != ttp && tp->tp_next != NULL;
4013 		    tp = tp->tp_next)
4014 		;
4015 	    ttp = tp;
4016 	}
4017     }
4018     else if (n == 9999)
4019     {
4020 	/* Go to last tab page. */
4021 	for (tp = first_tabpage; tp->tp_next != NULL; tp = tp->tp_next)
4022 	    ;
4023     }
4024     else
4025     {
4026 	/* Go to tab page "n". */
4027 	tp = find_tabpage(n);
4028 	if (tp == NULL)
4029 	{
4030 	    beep_flush();
4031 	    return;
4032 	}
4033     }
4034 
4035     goto_tabpage_tp(tp, TRUE, TRUE);
4036 
4037 #ifdef FEAT_GUI_TABLINE
4038     if (gui_use_tabline())
4039 	gui_mch_set_curtab(tabpage_index(curtab));
4040 #endif
4041 }
4042 
4043 /*
4044  * Go to tabpage "tp".
4045  * Only trigger *Enter autocommands when trigger_enter_autocmds is TRUE.
4046  * Only trigger *Leave autocommands when trigger_leave_autocmds is TRUE.
4047  * Note: doesn't update the GUI tab.
4048  */
4049     void
4050 goto_tabpage_tp(
4051     tabpage_T	*tp,
4052     int		trigger_enter_autocmds,
4053     int		trigger_leave_autocmds)
4054 {
4055     /* Don't repeat a message in another tab page. */
4056     set_keep_msg(NULL, 0);
4057 
4058     if (tp != curtab && leave_tabpage(tp->tp_curwin->w_buffer,
4059 					trigger_leave_autocmds) == OK)
4060     {
4061 	if (valid_tabpage(tp))
4062 	    enter_tabpage(tp, curbuf, trigger_enter_autocmds,
4063 		    trigger_leave_autocmds);
4064 	else
4065 	    enter_tabpage(curtab, curbuf, trigger_enter_autocmds,
4066 		    trigger_leave_autocmds);
4067     }
4068 }
4069 
4070 /*
4071  * Enter window "wp" in tab page "tp".
4072  * Also updates the GUI tab.
4073  */
4074     void
4075 goto_tabpage_win(tabpage_T *tp, win_T *wp)
4076 {
4077     goto_tabpage_tp(tp, TRUE, TRUE);
4078     if (curtab == tp && win_valid(wp))
4079     {
4080 	win_enter(wp, TRUE);
4081 # ifdef FEAT_GUI_TABLINE
4082 	if (gui_use_tabline())
4083 	    gui_mch_set_curtab(tabpage_index(curtab));
4084 # endif
4085     }
4086 }
4087 
4088 /*
4089  * Move the current tab page to after tab page "nr".
4090  */
4091     void
4092 tabpage_move(int nr)
4093 {
4094     int		n = 1;
4095     tabpage_T	*tp, *tp_dst;
4096 
4097     if (first_tabpage->tp_next == NULL)
4098 	return;
4099 
4100     for (tp = first_tabpage; tp->tp_next != NULL && n < nr; tp = tp->tp_next)
4101 	++n;
4102 
4103     if (tp == curtab || (nr > 0 && tp->tp_next != NULL
4104 						    && tp->tp_next == curtab))
4105 	return;
4106 
4107     tp_dst = tp;
4108 
4109     /* Remove the current tab page from the list of tab pages. */
4110     if (curtab == first_tabpage)
4111 	first_tabpage = curtab->tp_next;
4112     else
4113     {
4114 	FOR_ALL_TABPAGES(tp)
4115 	    if (tp->tp_next == curtab)
4116 		break;
4117 	if (tp == NULL)	/* "cannot happen" */
4118 	    return;
4119 	tp->tp_next = curtab->tp_next;
4120     }
4121 
4122     /* Re-insert it at the specified position. */
4123     if (nr <= 0)
4124     {
4125 	curtab->tp_next = first_tabpage;
4126 	first_tabpage = curtab;
4127     }
4128     else
4129     {
4130 	curtab->tp_next = tp_dst->tp_next;
4131 	tp_dst->tp_next = curtab;
4132     }
4133 
4134     /* Need to redraw the tabline.  Tab page contents doesn't change. */
4135     redraw_tabline = TRUE;
4136 }
4137 
4138 
4139 /*
4140  * Go to another window.
4141  * When jumping to another buffer, stop Visual mode.  Do this before
4142  * changing windows so we can yank the selection into the '*' register.
4143  * When jumping to another window on the same buffer, adjust its cursor
4144  * position to keep the same Visual area.
4145  */
4146     void
4147 win_goto(win_T *wp)
4148 {
4149 #ifdef FEAT_CONCEAL
4150     win_T	*owp = curwin;
4151 #endif
4152 
4153     if (text_locked())
4154     {
4155 	beep_flush();
4156 	text_locked_msg();
4157 	return;
4158     }
4159     if (curbuf_locked())
4160 	return;
4161 
4162     if (wp->w_buffer != curbuf)
4163 	reset_VIsual_and_resel();
4164     else if (VIsual_active)
4165 	wp->w_cursor = curwin->w_cursor;
4166 
4167 #ifdef FEAT_GUI
4168     need_mouse_correct = TRUE;
4169 #endif
4170     win_enter(wp, TRUE);
4171 
4172 #ifdef FEAT_CONCEAL
4173     // Conceal cursor line in previous window, unconceal in current window.
4174     if (win_valid(owp) && owp->w_p_cole > 0 && !msg_scrolled)
4175 	redrawWinline(owp, owp->w_cursor.lnum);
4176     if (curwin->w_p_cole > 0 && !msg_scrolled)
4177 	need_cursor_line_redraw = TRUE;
4178 #endif
4179 }
4180 
4181 #if defined(FEAT_PERL) || defined(PROTO)
4182 /*
4183  * Find window number "winnr" (counting top to bottom).
4184  */
4185     win_T *
4186 win_find_nr(int winnr)
4187 {
4188     win_T	*wp;
4189 
4190     FOR_ALL_WINDOWS(wp)
4191 	if (--winnr == 0)
4192 	    break;
4193     return wp;
4194 }
4195 #endif
4196 
4197 #if ((defined(FEAT_PYTHON) || defined(FEAT_PYTHON3))) || defined(PROTO)
4198 /*
4199  * Find the tabpage for window "win".
4200  */
4201     tabpage_T *
4202 win_find_tabpage(win_T *win)
4203 {
4204     win_T	*wp;
4205     tabpage_T	*tp;
4206 
4207     FOR_ALL_TAB_WINDOWS(tp, wp)
4208 	    if (wp == win)
4209 		return tp;
4210     return NULL;
4211 }
4212 #endif
4213 
4214 /*
4215  * Move to window above or below "count" times.
4216  */
4217     static void
4218 win_goto_ver(
4219     int		up,		/* TRUE to go to win above */
4220     long	count)
4221 {
4222     frame_T	*fr;
4223     frame_T	*nfr;
4224     frame_T	*foundfr;
4225 
4226     foundfr = curwin->w_frame;
4227     while (count--)
4228     {
4229 	/*
4230 	 * First go upwards in the tree of frames until we find a upwards or
4231 	 * downwards neighbor.
4232 	 */
4233 	fr = foundfr;
4234 	for (;;)
4235 	{
4236 	    if (fr == topframe)
4237 		goto end;
4238 	    if (up)
4239 		nfr = fr->fr_prev;
4240 	    else
4241 		nfr = fr->fr_next;
4242 	    if (fr->fr_parent->fr_layout == FR_COL && nfr != NULL)
4243 		break;
4244 	    fr = fr->fr_parent;
4245 	}
4246 
4247 	/*
4248 	 * Now go downwards to find the bottom or top frame in it.
4249 	 */
4250 	for (;;)
4251 	{
4252 	    if (nfr->fr_layout == FR_LEAF)
4253 	    {
4254 		foundfr = nfr;
4255 		break;
4256 	    }
4257 	    fr = nfr->fr_child;
4258 	    if (nfr->fr_layout == FR_ROW)
4259 	    {
4260 		/* Find the frame at the cursor row. */
4261 		while (fr->fr_next != NULL
4262 			&& frame2win(fr)->w_wincol + fr->fr_width
4263 					 <= curwin->w_wincol + curwin->w_wcol)
4264 		    fr = fr->fr_next;
4265 	    }
4266 	    if (nfr->fr_layout == FR_COL && up)
4267 		while (fr->fr_next != NULL)
4268 		    fr = fr->fr_next;
4269 	    nfr = fr;
4270 	}
4271     }
4272 end:
4273     if (foundfr != NULL)
4274 	win_goto(foundfr->fr_win);
4275 }
4276 
4277 /*
4278  * Move to left or right window.
4279  */
4280     static void
4281 win_goto_hor(
4282     int		left,		/* TRUE to go to left win */
4283     long	count)
4284 {
4285     frame_T	*fr;
4286     frame_T	*nfr;
4287     frame_T	*foundfr;
4288 
4289     foundfr = curwin->w_frame;
4290     while (count--)
4291     {
4292 	/*
4293 	 * First go upwards in the tree of frames until we find a left or
4294 	 * right neighbor.
4295 	 */
4296 	fr = foundfr;
4297 	for (;;)
4298 	{
4299 	    if (fr == topframe)
4300 		goto end;
4301 	    if (left)
4302 		nfr = fr->fr_prev;
4303 	    else
4304 		nfr = fr->fr_next;
4305 	    if (fr->fr_parent->fr_layout == FR_ROW && nfr != NULL)
4306 		break;
4307 	    fr = fr->fr_parent;
4308 	}
4309 
4310 	/*
4311 	 * Now go downwards to find the leftmost or rightmost frame in it.
4312 	 */
4313 	for (;;)
4314 	{
4315 	    if (nfr->fr_layout == FR_LEAF)
4316 	    {
4317 		foundfr = nfr;
4318 		break;
4319 	    }
4320 	    fr = nfr->fr_child;
4321 	    if (nfr->fr_layout == FR_COL)
4322 	    {
4323 		/* Find the frame at the cursor row. */
4324 		while (fr->fr_next != NULL
4325 			&& frame2win(fr)->w_winrow + fr->fr_height
4326 					 <= curwin->w_winrow + curwin->w_wrow)
4327 		    fr = fr->fr_next;
4328 	    }
4329 	    if (nfr->fr_layout == FR_ROW && left)
4330 		while (fr->fr_next != NULL)
4331 		    fr = fr->fr_next;
4332 	    nfr = fr;
4333 	}
4334     }
4335 end:
4336     if (foundfr != NULL)
4337 	win_goto(foundfr->fr_win);
4338 }
4339 
4340 /*
4341  * Make window "wp" the current window.
4342  */
4343     void
4344 win_enter(win_T *wp, int undo_sync)
4345 {
4346     win_enter_ext(wp, undo_sync, FALSE, FALSE, TRUE, TRUE);
4347 }
4348 
4349 /*
4350  * Make window wp the current window.
4351  * Can be called with "curwin_invalid" TRUE, which means that curwin has just
4352  * been closed and isn't valid.
4353  */
4354     static void
4355 win_enter_ext(
4356     win_T	*wp,
4357     int		undo_sync,
4358     int		curwin_invalid,
4359     int		trigger_new_autocmds,
4360     int		trigger_enter_autocmds,
4361     int		trigger_leave_autocmds)
4362 {
4363     int		other_buffer = FALSE;
4364 
4365     if (wp == curwin && !curwin_invalid)	/* nothing to do */
4366 	return;
4367 
4368 #ifdef FEAT_JOB_CHANNEL
4369     if (!curwin_invalid)
4370 	leaving_window(curwin);
4371 #endif
4372 
4373     if (!curwin_invalid && trigger_leave_autocmds)
4374     {
4375 	/*
4376 	 * Be careful: If autocommands delete the window, return now.
4377 	 */
4378 	if (wp->w_buffer != curbuf)
4379 	{
4380 	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
4381 	    other_buffer = TRUE;
4382 	    if (!win_valid(wp))
4383 		return;
4384 	}
4385 	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
4386 	if (!win_valid(wp))
4387 	    return;
4388 #ifdef FEAT_EVAL
4389 	/* autocmds may abort script processing */
4390 	if (aborting())
4391 	    return;
4392 #endif
4393     }
4394 
4395     /* sync undo before leaving the current buffer */
4396     if (undo_sync && curbuf != wp->w_buffer)
4397 	u_sync(FALSE);
4398 
4399     /* Might need to scroll the old window before switching, e.g., when the
4400      * cursor was moved. */
4401     update_topline();
4402 
4403     /* may have to copy the buffer options when 'cpo' contains 'S' */
4404     if (wp->w_buffer != curbuf)
4405 	buf_copy_options(wp->w_buffer, BCO_ENTER | BCO_NOHELP);
4406     if (!curwin_invalid)
4407     {
4408 	prevwin = curwin;	/* remember for CTRL-W p */
4409 	curwin->w_redr_status = TRUE;
4410     }
4411     curwin = wp;
4412     curbuf = wp->w_buffer;
4413     check_cursor();
4414     if (!virtual_active())
4415 	curwin->w_cursor.coladd = 0;
4416     changed_line_abv_curs();	/* assume cursor position needs updating */
4417 
4418     if (curwin->w_localdir != NULL)
4419     {
4420 	/* Window has a local directory: Save current directory as global
4421 	 * directory (unless that was done already) and change to the local
4422 	 * directory. */
4423 	if (globaldir == NULL)
4424 	{
4425 	    char_u	cwd[MAXPATHL];
4426 
4427 	    if (mch_dirname(cwd, MAXPATHL) == OK)
4428 		globaldir = vim_strsave(cwd);
4429 	}
4430 	if (mch_chdir((char *)curwin->w_localdir) == 0)
4431 	    shorten_fnames(TRUE);
4432     }
4433     else if (globaldir != NULL)
4434     {
4435 	/* Window doesn't have a local directory and we are not in the global
4436 	 * directory: Change to the global directory. */
4437 	vim_ignored = mch_chdir((char *)globaldir);
4438 	VIM_CLEAR(globaldir);
4439 	shorten_fnames(TRUE);
4440     }
4441 
4442 #ifdef FEAT_JOB_CHANNEL
4443     entering_window(curwin);
4444 #endif
4445     if (trigger_new_autocmds)
4446 	apply_autocmds(EVENT_WINNEW, NULL, NULL, FALSE, curbuf);
4447     if (trigger_enter_autocmds)
4448     {
4449 	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
4450 	if (other_buffer)
4451 	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
4452     }
4453 
4454 #ifdef FEAT_TITLE
4455     maketitle();
4456 #endif
4457     curwin->w_redr_status = TRUE;
4458     redraw_tabline = TRUE;
4459     if (restart_edit)
4460 	redraw_later(VALID);	/* causes status line redraw */
4461 
4462     /* set window height to desired minimal value */
4463     if (curwin->w_height < p_wh && !curwin->w_p_wfh)
4464 	win_setheight((int)p_wh);
4465     else if (curwin->w_height == 0)
4466 	win_setheight(1);
4467 
4468     /* set window width to desired minimal value */
4469     if (curwin->w_width < p_wiw && !curwin->w_p_wfw)
4470 	win_setwidth((int)p_wiw);
4471 
4472 #ifdef FEAT_MOUSE
4473     setmouse();			/* in case jumped to/from help buffer */
4474 #endif
4475 
4476     /* Change directories when the 'acd' option is set. */
4477     DO_AUTOCHDIR;
4478 }
4479 
4480 
4481 /*
4482  * Jump to the first open window that contains buffer "buf", if one exists.
4483  * Returns a pointer to the window found, otherwise NULL.
4484  */
4485     win_T *
4486 buf_jump_open_win(buf_T *buf)
4487 {
4488     win_T	*wp = NULL;
4489 
4490     if (curwin->w_buffer == buf)
4491 	wp = curwin;
4492     else
4493 	FOR_ALL_WINDOWS(wp)
4494 	    if (wp->w_buffer == buf)
4495 		break;
4496     if (wp != NULL)
4497 	win_enter(wp, FALSE);
4498     return wp;
4499 }
4500 
4501 /*
4502  * Jump to the first open window in any tab page that contains buffer "buf",
4503  * if one exists.
4504  * Returns a pointer to the window found, otherwise NULL.
4505  */
4506     win_T *
4507 buf_jump_open_tab(buf_T *buf)
4508 {
4509     win_T	*wp = buf_jump_open_win(buf);
4510     tabpage_T	*tp;
4511 
4512     if (wp != NULL)
4513 	return wp;
4514 
4515     FOR_ALL_TABPAGES(tp)
4516 	if (tp != curtab)
4517 	{
4518 	    for (wp = tp->tp_firstwin; wp != NULL; wp = wp->w_next)
4519 		if (wp->w_buffer == buf)
4520 		    break;
4521 	    if (wp != NULL)
4522 	    {
4523 		goto_tabpage_win(tp, wp);
4524 		if (curwin != wp)
4525 		    wp = NULL;	/* something went wrong */
4526 		break;
4527 	    }
4528 	}
4529     return wp;
4530 }
4531 
4532 static int last_win_id = LOWEST_WIN_ID - 1;
4533 
4534 /*
4535  * Allocate a window structure and link it in the window list when "hidden" is
4536  * FALSE.
4537  */
4538     static win_T *
4539 win_alloc(win_T *after UNUSED, int hidden UNUSED)
4540 {
4541     win_T	*new_wp;
4542 
4543     /*
4544      * allocate window structure and linesizes arrays
4545      */
4546     new_wp = (win_T *)alloc_clear((unsigned)sizeof(win_T));
4547     if (new_wp == NULL)
4548 	return NULL;
4549 
4550     if (win_alloc_lines(new_wp) == FAIL)
4551     {
4552 	vim_free(new_wp);
4553 	return NULL;
4554     }
4555 
4556     new_wp->w_id = ++last_win_id;
4557 
4558 #ifdef FEAT_EVAL
4559     /* init w: variables */
4560     new_wp->w_vars = dict_alloc();
4561     if (new_wp->w_vars == NULL)
4562     {
4563 	win_free_lsize(new_wp);
4564 	vim_free(new_wp);
4565 	return NULL;
4566     }
4567     init_var_dict(new_wp->w_vars, &new_wp->w_winvar, VAR_SCOPE);
4568 #endif
4569 
4570     /* Don't execute autocommands while the window is not properly
4571      * initialized yet.  gui_create_scrollbar() may trigger a FocusGained
4572      * event. */
4573     block_autocmds();
4574 
4575     /*
4576      * link the window in the window list
4577      */
4578     if (!hidden)
4579 	win_append(after, new_wp);
4580     new_wp->w_wincol = 0;
4581     new_wp->w_width = Columns;
4582 
4583     /* position the display and the cursor at the top of the file. */
4584     new_wp->w_topline = 1;
4585 #ifdef FEAT_DIFF
4586     new_wp->w_topfill = 0;
4587 #endif
4588     new_wp->w_botline = 2;
4589     new_wp->w_cursor.lnum = 1;
4590     new_wp->w_scbind_pos = 1;
4591 
4592     // use global option value for global-local options
4593     new_wp->w_p_so = -1;
4594     new_wp->w_p_siso = -1;
4595 
4596     /* We won't calculate w_fraction until resizing the window */
4597     new_wp->w_fraction = 0;
4598     new_wp->w_prev_fraction_row = -1;
4599 
4600 #ifdef FEAT_GUI
4601     if (gui.in_use)
4602     {
4603 	gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_LEFT],
4604 		SBAR_LEFT, new_wp);
4605 	gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_RIGHT],
4606 		SBAR_RIGHT, new_wp);
4607     }
4608 #endif
4609 #ifdef FEAT_FOLDING
4610     foldInitWin(new_wp);
4611 #endif
4612     unblock_autocmds();
4613 #ifdef FEAT_SEARCH_EXTRA
4614     new_wp->w_match_head = NULL;
4615     new_wp->w_next_match_id = 4;
4616 #endif
4617     return new_wp;
4618 }
4619 
4620 /*
4621  * Remove window 'wp' from the window list and free the structure.
4622  */
4623     static void
4624 win_free(
4625     win_T	*wp,
4626     tabpage_T	*tp)		/* tab page "win" is in, NULL for current */
4627 {
4628     int		i;
4629     buf_T	*buf;
4630     wininfo_T	*wip;
4631 
4632 #ifdef FEAT_FOLDING
4633     clearFolding(wp);
4634 #endif
4635 
4636     /* reduce the reference count to the argument list. */
4637     alist_unlink(wp->w_alist);
4638 
4639     /* Don't execute autocommands while the window is halfway being deleted.
4640      * gui_mch_destroy_scrollbar() may trigger a FocusGained event. */
4641     block_autocmds();
4642 
4643 #ifdef FEAT_LUA
4644     lua_window_free(wp);
4645 #endif
4646 
4647 #ifdef FEAT_MZSCHEME
4648     mzscheme_window_free(wp);
4649 #endif
4650 
4651 #ifdef FEAT_PERL
4652     perl_win_free(wp);
4653 #endif
4654 
4655 #ifdef FEAT_PYTHON
4656     python_window_free(wp);
4657 #endif
4658 
4659 #ifdef FEAT_PYTHON3
4660     python3_window_free(wp);
4661 #endif
4662 
4663 #ifdef FEAT_TCL
4664     tcl_window_free(wp);
4665 #endif
4666 
4667 #ifdef FEAT_RUBY
4668     ruby_window_free(wp);
4669 #endif
4670 
4671     clear_winopt(&wp->w_onebuf_opt);
4672     clear_winopt(&wp->w_allbuf_opt);
4673 
4674 #ifdef FEAT_EVAL
4675     vars_clear(&wp->w_vars->dv_hashtab);	/* free all w: variables */
4676     hash_init(&wp->w_vars->dv_hashtab);
4677     unref_var_dict(wp->w_vars);
4678 #endif
4679 
4680     {
4681 	tabpage_T	*ttp;
4682 
4683 	if (prevwin == wp)
4684 	    prevwin = NULL;
4685 	FOR_ALL_TABPAGES(ttp)
4686 	    if (ttp->tp_prevwin == wp)
4687 		ttp->tp_prevwin = NULL;
4688     }
4689     win_free_lsize(wp);
4690 
4691     for (i = 0; i < wp->w_tagstacklen; ++i)
4692 	vim_free(wp->w_tagstack[i].tagname);
4693 
4694     vim_free(wp->w_localdir);
4695 
4696     /* Remove the window from the b_wininfo lists, it may happen that the
4697      * freed memory is re-used for another window. */
4698     FOR_ALL_BUFFERS(buf)
4699 	for (wip = buf->b_wininfo; wip != NULL; wip = wip->wi_next)
4700 	    if (wip->wi_win == wp)
4701 		wip->wi_win = NULL;
4702 
4703 #ifdef FEAT_SEARCH_EXTRA
4704     clear_matches(wp);
4705 #endif
4706 
4707 #ifdef FEAT_JUMPLIST
4708     free_jumplist(wp);
4709 #endif
4710 
4711 #ifdef FEAT_QUICKFIX
4712     qf_free_all(wp);
4713 #endif
4714 
4715 #ifdef FEAT_GUI
4716     if (gui.in_use)
4717     {
4718 	gui_mch_destroy_scrollbar(&wp->w_scrollbars[SBAR_LEFT]);
4719 	gui_mch_destroy_scrollbar(&wp->w_scrollbars[SBAR_RIGHT]);
4720     }
4721 #endif /* FEAT_GUI */
4722 
4723 #ifdef FEAT_MENU
4724     remove_winbar(wp);
4725 #endif
4726 
4727 #ifdef FEAT_SYN_HL
4728     vim_free(wp->w_p_cc_cols);
4729 #endif
4730 
4731     if (wp != aucmd_win)
4732 	win_remove(wp, tp);
4733     if (autocmd_busy)
4734     {
4735 	wp->w_next = au_pending_free_win;
4736 	au_pending_free_win = wp;
4737     }
4738     else
4739 	vim_free(wp);
4740 
4741     unblock_autocmds();
4742 }
4743 
4744 /*
4745  * Append window "wp" in the window list after window "after".
4746  */
4747     void
4748 win_append(win_T *after, win_T *wp)
4749 {
4750     win_T	*before;
4751 
4752     if (after == NULL)	    /* after NULL is in front of the first */
4753 	before = firstwin;
4754     else
4755 	before = after->w_next;
4756 
4757     wp->w_next = before;
4758     wp->w_prev = after;
4759     if (after == NULL)
4760 	firstwin = wp;
4761     else
4762 	after->w_next = wp;
4763     if (before == NULL)
4764 	lastwin = wp;
4765     else
4766 	before->w_prev = wp;
4767 }
4768 
4769 /*
4770  * Remove a window from the window list.
4771  */
4772     void
4773 win_remove(
4774     win_T	*wp,
4775     tabpage_T	*tp)		/* tab page "win" is in, NULL for current */
4776 {
4777     if (wp->w_prev != NULL)
4778 	wp->w_prev->w_next = wp->w_next;
4779     else if (tp == NULL)
4780 	firstwin = curtab->tp_firstwin = wp->w_next;
4781     else
4782 	tp->tp_firstwin = wp->w_next;
4783 
4784     if (wp->w_next != NULL)
4785 	wp->w_next->w_prev = wp->w_prev;
4786     else if (tp == NULL)
4787 	lastwin = curtab->tp_lastwin = wp->w_prev;
4788     else
4789 	tp->tp_lastwin = wp->w_prev;
4790 }
4791 
4792 /*
4793  * Append frame "frp" in a frame list after frame "after".
4794  */
4795     static void
4796 frame_append(frame_T *after, frame_T *frp)
4797 {
4798     frp->fr_next = after->fr_next;
4799     after->fr_next = frp;
4800     if (frp->fr_next != NULL)
4801 	frp->fr_next->fr_prev = frp;
4802     frp->fr_prev = after;
4803 }
4804 
4805 /*
4806  * Insert frame "frp" in a frame list before frame "before".
4807  */
4808     static void
4809 frame_insert(frame_T *before, frame_T *frp)
4810 {
4811     frp->fr_next = before;
4812     frp->fr_prev = before->fr_prev;
4813     before->fr_prev = frp;
4814     if (frp->fr_prev != NULL)
4815 	frp->fr_prev->fr_next = frp;
4816     else
4817 	frp->fr_parent->fr_child = frp;
4818 }
4819 
4820 /*
4821  * Remove a frame from a frame list.
4822  */
4823     static void
4824 frame_remove(frame_T *frp)
4825 {
4826     if (frp->fr_prev != NULL)
4827 	frp->fr_prev->fr_next = frp->fr_next;
4828     else
4829     {
4830 	frp->fr_parent->fr_child = frp->fr_next;
4831 	/* special case: topframe->fr_child == frp */
4832 	if (topframe->fr_child == frp)
4833 	    topframe->fr_child = frp->fr_next;
4834     }
4835     if (frp->fr_next != NULL)
4836 	frp->fr_next->fr_prev = frp->fr_prev;
4837 }
4838 
4839 /*
4840  * Allocate w_lines[] for window "wp".
4841  * Return FAIL for failure, OK for success.
4842  */
4843     int
4844 win_alloc_lines(win_T *wp)
4845 {
4846     wp->w_lines_valid = 0;
4847     wp->w_lines = (wline_T *)alloc_clear((unsigned)(Rows * sizeof(wline_T)));
4848     if (wp->w_lines == NULL)
4849 	return FAIL;
4850     return OK;
4851 }
4852 
4853 /*
4854  * free lsize arrays for a window
4855  */
4856     void
4857 win_free_lsize(win_T *wp)
4858 {
4859     /* TODO: why would wp be NULL here? */
4860     if (wp != NULL)
4861 	VIM_CLEAR(wp->w_lines);
4862 }
4863 
4864 /*
4865  * Called from win_new_shellsize() after Rows changed.
4866  * This only does the current tab page, others must be done when made active.
4867  */
4868     void
4869 shell_new_rows(void)
4870 {
4871     int		h = (int)ROWS_AVAIL;
4872 
4873     if (firstwin == NULL)	/* not initialized yet */
4874 	return;
4875     if (h < frame_minheight(topframe, NULL))
4876 	h = frame_minheight(topframe, NULL);
4877 
4878     /* First try setting the heights of windows with 'winfixheight'.  If
4879      * that doesn't result in the right height, forget about that option. */
4880     frame_new_height(topframe, h, FALSE, TRUE);
4881     if (!frame_check_height(topframe, h))
4882 	frame_new_height(topframe, h, FALSE, FALSE);
4883 
4884     (void)win_comp_pos();		/* recompute w_winrow and w_wincol */
4885     compute_cmdrow();
4886     curtab->tp_ch_used = p_ch;
4887 
4888 #if 0
4889     /* Disabled: don't want making the screen smaller make a window larger. */
4890     if (p_ea)
4891 	win_equal(curwin, FALSE, 'v');
4892 #endif
4893 }
4894 
4895 /*
4896  * Called from win_new_shellsize() after Columns changed.
4897  */
4898     void
4899 shell_new_columns(void)
4900 {
4901     if (firstwin == NULL)	/* not initialized yet */
4902 	return;
4903 
4904     /* First try setting the widths of windows with 'winfixwidth'.  If that
4905      * doesn't result in the right width, forget about that option. */
4906     frame_new_width(topframe, (int)Columns, FALSE, TRUE);
4907     if (!frame_check_width(topframe, Columns))
4908 	frame_new_width(topframe, (int)Columns, FALSE, FALSE);
4909 
4910     (void)win_comp_pos();		/* recompute w_winrow and w_wincol */
4911 #if 0
4912     /* Disabled: don't want making the screen smaller make a window larger. */
4913     if (p_ea)
4914 	win_equal(curwin, FALSE, 'h');
4915 #endif
4916 }
4917 
4918 #if defined(FEAT_CMDWIN) || defined(PROTO)
4919 /*
4920  * Save the size of all windows in "gap".
4921  */
4922     void
4923 win_size_save(garray_T *gap)
4924 
4925 {
4926     win_T	*wp;
4927 
4928     ga_init2(gap, (int)sizeof(int), 1);
4929     if (ga_grow(gap, win_count() * 2) == OK)
4930 	FOR_ALL_WINDOWS(wp)
4931 	{
4932 	    ((int *)gap->ga_data)[gap->ga_len++] =
4933 					       wp->w_width + wp->w_vsep_width;
4934 	    ((int *)gap->ga_data)[gap->ga_len++] = wp->w_height;
4935 	}
4936 }
4937 
4938 /*
4939  * Restore window sizes, but only if the number of windows is still the same.
4940  * Does not free the growarray.
4941  */
4942     void
4943 win_size_restore(garray_T *gap)
4944 {
4945     win_T	*wp;
4946     int		i, j;
4947 
4948     if (win_count() * 2 == gap->ga_len)
4949     {
4950 	/* The order matters, because frames contain other frames, but it's
4951 	 * difficult to get right. The easy way out is to do it twice. */
4952 	for (j = 0; j < 2; ++j)
4953 	{
4954 	    i = 0;
4955 	    FOR_ALL_WINDOWS(wp)
4956 	    {
4957 		frame_setwidth(wp->w_frame, ((int *)gap->ga_data)[i++]);
4958 		win_setheight_win(((int *)gap->ga_data)[i++], wp);
4959 	    }
4960 	}
4961 	/* recompute the window positions */
4962 	(void)win_comp_pos();
4963     }
4964 }
4965 #endif /* FEAT_CMDWIN */
4966 
4967 /*
4968  * Update the position for all windows, using the width and height of the
4969  * frames.
4970  * Returns the row just after the last window.
4971  */
4972     int
4973 win_comp_pos(void)
4974 {
4975     int		row = tabline_height();
4976     int		col = 0;
4977 
4978     frame_comp_pos(topframe, &row, &col);
4979     return row;
4980 }
4981 
4982 /*
4983  * Update the position of the windows in frame "topfrp", using the width and
4984  * height of the frames.
4985  * "*row" and "*col" are the top-left position of the frame.  They are updated
4986  * to the bottom-right position plus one.
4987  */
4988     static void
4989 frame_comp_pos(frame_T *topfrp, int *row, int *col)
4990 {
4991     win_T	*wp;
4992     frame_T	*frp;
4993     int		startcol;
4994     int		startrow;
4995     int		h;
4996 
4997     wp = topfrp->fr_win;
4998     if (wp != NULL)
4999     {
5000 	if (wp->w_winrow != *row || wp->w_wincol != *col)
5001 	{
5002 	    /* position changed, redraw */
5003 	    wp->w_winrow = *row;
5004 	    wp->w_wincol = *col;
5005 	    redraw_win_later(wp, NOT_VALID);
5006 	    wp->w_redr_status = TRUE;
5007 	}
5008 	/* WinBar will not show if the window height is zero */
5009 	h = VISIBLE_HEIGHT(wp) + wp->w_status_height;
5010 	*row += h > topfrp->fr_height ? topfrp->fr_height : h;
5011 	*col += wp->w_width + wp->w_vsep_width;
5012     }
5013     else
5014     {
5015 	startrow = *row;
5016 	startcol = *col;
5017 	FOR_ALL_FRAMES(frp, topfrp->fr_child)
5018 	{
5019 	    if (topfrp->fr_layout == FR_ROW)
5020 		*row = startrow;	/* all frames are at the same row */
5021 	    else
5022 		*col = startcol;	/* all frames are at the same col */
5023 	    frame_comp_pos(frp, row, col);
5024 	}
5025     }
5026 }
5027 
5028 /*
5029  * Set current window height and take care of repositioning other windows to
5030  * fit around it.
5031  */
5032     void
5033 win_setheight(int height)
5034 {
5035     win_setheight_win(height, curwin);
5036 }
5037 
5038 /*
5039  * Set the window height of window "win" and take care of repositioning other
5040  * windows to fit around it.
5041  */
5042     void
5043 win_setheight_win(int height, win_T *win)
5044 {
5045     int		row;
5046 
5047     if (win == curwin)
5048     {
5049 	/* Always keep current window at least one line high, even when
5050 	 * 'winminheight' is zero. */
5051 	if (height < p_wmh)
5052 	    height = p_wmh;
5053 	if (height == 0)
5054 	    height = 1;
5055 	height += WINBAR_HEIGHT(curwin);
5056     }
5057 
5058     frame_setheight(win->w_frame, height + win->w_status_height);
5059 
5060     /* recompute the window positions */
5061     row = win_comp_pos();
5062 
5063     /*
5064      * If there is extra space created between the last window and the command
5065      * line, clear it.
5066      */
5067     if (full_screen && msg_scrolled == 0 && row < cmdline_row)
5068 	screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
5069     cmdline_row = row;
5070     msg_row = row;
5071     msg_col = 0;
5072 
5073     redraw_all_later(NOT_VALID);
5074 }
5075 
5076 /*
5077  * Set the height of a frame to "height" and take care that all frames and
5078  * windows inside it are resized.  Also resize frames on the left and right if
5079  * the are in the same FR_ROW frame.
5080  *
5081  * Strategy:
5082  * If the frame is part of a FR_COL frame, try fitting the frame in that
5083  * frame.  If that doesn't work (the FR_COL frame is too small), recursively
5084  * go to containing frames to resize them and make room.
5085  * If the frame is part of a FR_ROW frame, all frames must be resized as well.
5086  * Check for the minimal height of the FR_ROW frame.
5087  * At the top level we can also use change the command line height.
5088  */
5089     static void
5090 frame_setheight(frame_T *curfrp, int height)
5091 {
5092     int		room;		/* total number of lines available */
5093     int		take;		/* number of lines taken from other windows */
5094     int		room_cmdline;	/* lines available from cmdline */
5095     int		run;
5096     frame_T	*frp;
5097     int		h;
5098     int		room_reserved;
5099 
5100     /* If the height already is the desired value, nothing to do. */
5101     if (curfrp->fr_height == height)
5102 	return;
5103 
5104     if (curfrp->fr_parent == NULL)
5105     {
5106 	/* topframe: can only change the command line */
5107 	if (height > ROWS_AVAIL)
5108 	    height = ROWS_AVAIL;
5109 	if (height > 0)
5110 	    frame_new_height(curfrp, height, FALSE, FALSE);
5111     }
5112     else if (curfrp->fr_parent->fr_layout == FR_ROW)
5113     {
5114 	/* Row of frames: Also need to resize frames left and right of this
5115 	 * one.  First check for the minimal height of these. */
5116 	h = frame_minheight(curfrp->fr_parent, NULL);
5117 	if (height < h)
5118 	    height = h;
5119 	frame_setheight(curfrp->fr_parent, height);
5120     }
5121     else
5122     {
5123 	/*
5124 	 * Column of frames: try to change only frames in this column.
5125 	 */
5126 	/*
5127 	 * Do this twice:
5128 	 * 1: compute room available, if it's not enough try resizing the
5129 	 *    containing frame.
5130 	 * 2: compute the room available and adjust the height to it.
5131 	 * Try not to reduce the height of a window with 'winfixheight' set.
5132 	 */
5133 	for (run = 1; run <= 2; ++run)
5134 	{
5135 	    room = 0;
5136 	    room_reserved = 0;
5137 	    FOR_ALL_FRAMES(frp, curfrp->fr_parent->fr_child)
5138 	    {
5139 		if (frp != curfrp
5140 			&& frp->fr_win != NULL
5141 			&& frp->fr_win->w_p_wfh)
5142 		    room_reserved += frp->fr_height;
5143 		room += frp->fr_height;
5144 		if (frp != curfrp)
5145 		    room -= frame_minheight(frp, NULL);
5146 	    }
5147 	    if (curfrp->fr_width != Columns)
5148 		room_cmdline = 0;
5149 	    else
5150 	    {
5151 		room_cmdline = Rows - p_ch - (lastwin->w_winrow
5152 						+ VISIBLE_HEIGHT(lastwin)
5153 						+ lastwin->w_status_height);
5154 		if (room_cmdline < 0)
5155 		    room_cmdline = 0;
5156 	    }
5157 
5158 	    if (height <= room + room_cmdline)
5159 		break;
5160 	    if (run == 2 || curfrp->fr_width == Columns)
5161 	    {
5162 		if (height > room + room_cmdline)
5163 		    height = room + room_cmdline;
5164 		break;
5165 	    }
5166 	    frame_setheight(curfrp->fr_parent, height
5167 		+ frame_minheight(curfrp->fr_parent, NOWIN) - (int)p_wmh - 1);
5168 	}
5169 
5170 	/*
5171 	 * Compute the number of lines we will take from others frames (can be
5172 	 * negative!).
5173 	 */
5174 	take = height - curfrp->fr_height;
5175 
5176 	/* If there is not enough room, also reduce the height of a window
5177 	 * with 'winfixheight' set. */
5178 	if (height > room + room_cmdline - room_reserved)
5179 	    room_reserved = room + room_cmdline - height;
5180 	/* If there is only a 'winfixheight' window and making the
5181 	 * window smaller, need to make the other window taller. */
5182 	if (take < 0 && room - curfrp->fr_height < room_reserved)
5183 	    room_reserved = 0;
5184 
5185 	if (take > 0 && room_cmdline > 0)
5186 	{
5187 	    /* use lines from cmdline first */
5188 	    if (take < room_cmdline)
5189 		room_cmdline = take;
5190 	    take -= room_cmdline;
5191 	    topframe->fr_height += room_cmdline;
5192 	}
5193 
5194 	/*
5195 	 * set the current frame to the new height
5196 	 */
5197 	frame_new_height(curfrp, height, FALSE, FALSE);
5198 
5199 	/*
5200 	 * First take lines from the frames after the current frame.  If
5201 	 * that is not enough, takes lines from frames above the current
5202 	 * frame.
5203 	 */
5204 	for (run = 0; run < 2; ++run)
5205 	{
5206 	    if (run == 0)
5207 		frp = curfrp->fr_next;	/* 1st run: start with next window */
5208 	    else
5209 		frp = curfrp->fr_prev;	/* 2nd run: start with prev window */
5210 	    while (frp != NULL && take != 0)
5211 	    {
5212 		h = frame_minheight(frp, NULL);
5213 		if (room_reserved > 0
5214 			&& frp->fr_win != NULL
5215 			&& frp->fr_win->w_p_wfh)
5216 		{
5217 		    if (room_reserved >= frp->fr_height)
5218 			room_reserved -= frp->fr_height;
5219 		    else
5220 		    {
5221 			if (frp->fr_height - room_reserved > take)
5222 			    room_reserved = frp->fr_height - take;
5223 			take -= frp->fr_height - room_reserved;
5224 			frame_new_height(frp, room_reserved, FALSE, FALSE);
5225 			room_reserved = 0;
5226 		    }
5227 		}
5228 		else
5229 		{
5230 		    if (frp->fr_height - take < h)
5231 		    {
5232 			take -= frp->fr_height - h;
5233 			frame_new_height(frp, h, FALSE, FALSE);
5234 		    }
5235 		    else
5236 		    {
5237 			frame_new_height(frp, frp->fr_height - take,
5238 								FALSE, FALSE);
5239 			take = 0;
5240 		    }
5241 		}
5242 		if (run == 0)
5243 		    frp = frp->fr_next;
5244 		else
5245 		    frp = frp->fr_prev;
5246 	    }
5247 	}
5248     }
5249 }
5250 
5251 /*
5252  * Set current window width and take care of repositioning other windows to
5253  * fit around it.
5254  */
5255     void
5256 win_setwidth(int width)
5257 {
5258     win_setwidth_win(width, curwin);
5259 }
5260 
5261     void
5262 win_setwidth_win(int width, win_T *wp)
5263 {
5264     /* Always keep current window at least one column wide, even when
5265      * 'winminwidth' is zero. */
5266     if (wp == curwin)
5267     {
5268 	if (width < p_wmw)
5269 	    width = p_wmw;
5270 	if (width == 0)
5271 	    width = 1;
5272     }
5273 
5274     frame_setwidth(wp->w_frame, width + wp->w_vsep_width);
5275 
5276     /* recompute the window positions */
5277     (void)win_comp_pos();
5278 
5279     redraw_all_later(NOT_VALID);
5280 }
5281 
5282 /*
5283  * Set the width of a frame to "width" and take care that all frames and
5284  * windows inside it are resized.  Also resize frames above and below if the
5285  * are in the same FR_ROW frame.
5286  *
5287  * Strategy is similar to frame_setheight().
5288  */
5289     static void
5290 frame_setwidth(frame_T *curfrp, int width)
5291 {
5292     int		room;		/* total number of lines available */
5293     int		take;		/* number of lines taken from other windows */
5294     int		run;
5295     frame_T	*frp;
5296     int		w;
5297     int		room_reserved;
5298 
5299     /* If the width already is the desired value, nothing to do. */
5300     if (curfrp->fr_width == width)
5301 	return;
5302 
5303     if (curfrp->fr_parent == NULL)
5304 	/* topframe: can't change width */
5305 	return;
5306 
5307     if (curfrp->fr_parent->fr_layout == FR_COL)
5308     {
5309 	/* Column of frames: Also need to resize frames above and below of
5310 	 * this one.  First check for the minimal width of these. */
5311 	w = frame_minwidth(curfrp->fr_parent, NULL);
5312 	if (width < w)
5313 	    width = w;
5314 	frame_setwidth(curfrp->fr_parent, width);
5315     }
5316     else
5317     {
5318 	/*
5319 	 * Row of frames: try to change only frames in this row.
5320 	 *
5321 	 * Do this twice:
5322 	 * 1: compute room available, if it's not enough try resizing the
5323 	 *    containing frame.
5324 	 * 2: compute the room available and adjust the width to it.
5325 	 */
5326 	for (run = 1; run <= 2; ++run)
5327 	{
5328 	    room = 0;
5329 	    room_reserved = 0;
5330 	    FOR_ALL_FRAMES(frp, curfrp->fr_parent->fr_child)
5331 	    {
5332 		if (frp != curfrp
5333 			&& frp->fr_win != NULL
5334 			&& frp->fr_win->w_p_wfw)
5335 		    room_reserved += frp->fr_width;
5336 		room += frp->fr_width;
5337 		if (frp != curfrp)
5338 		    room -= frame_minwidth(frp, NULL);
5339 	    }
5340 
5341 	    if (width <= room)
5342 		break;
5343 	    if (run == 2 || curfrp->fr_height >= ROWS_AVAIL)
5344 	    {
5345 		if (width > room)
5346 		    width = room;
5347 		break;
5348 	    }
5349 	    frame_setwidth(curfrp->fr_parent, width
5350 		 + frame_minwidth(curfrp->fr_parent, NOWIN) - (int)p_wmw - 1);
5351 	}
5352 
5353 	/*
5354 	 * Compute the number of lines we will take from others frames (can be
5355 	 * negative!).
5356 	 */
5357 	take = width - curfrp->fr_width;
5358 
5359 	/* If there is not enough room, also reduce the width of a window
5360 	 * with 'winfixwidth' set. */
5361 	if (width > room - room_reserved)
5362 	    room_reserved = room - width;
5363 	/* If there is only a 'winfixwidth' window and making the
5364 	 * window smaller, need to make the other window narrower. */
5365 	if (take < 0 && room - curfrp->fr_width < room_reserved)
5366 	    room_reserved = 0;
5367 
5368 	/*
5369 	 * set the current frame to the new width
5370 	 */
5371 	frame_new_width(curfrp, width, FALSE, FALSE);
5372 
5373 	/*
5374 	 * First take lines from the frames right of the current frame.  If
5375 	 * that is not enough, takes lines from frames left of the current
5376 	 * frame.
5377 	 */
5378 	for (run = 0; run < 2; ++run)
5379 	{
5380 	    if (run == 0)
5381 		frp = curfrp->fr_next;	/* 1st run: start with next window */
5382 	    else
5383 		frp = curfrp->fr_prev;	/* 2nd run: start with prev window */
5384 	    while (frp != NULL && take != 0)
5385 	    {
5386 		w = frame_minwidth(frp, NULL);
5387 		if (room_reserved > 0
5388 			&& frp->fr_win != NULL
5389 			&& frp->fr_win->w_p_wfw)
5390 		{
5391 		    if (room_reserved >= frp->fr_width)
5392 			room_reserved -= frp->fr_width;
5393 		    else
5394 		    {
5395 			if (frp->fr_width - room_reserved > take)
5396 			    room_reserved = frp->fr_width - take;
5397 			take -= frp->fr_width - room_reserved;
5398 			frame_new_width(frp, room_reserved, FALSE, FALSE);
5399 			room_reserved = 0;
5400 		    }
5401 		}
5402 		else
5403 		{
5404 		    if (frp->fr_width - take < w)
5405 		    {
5406 			take -= frp->fr_width - w;
5407 			frame_new_width(frp, w, FALSE, FALSE);
5408 		    }
5409 		    else
5410 		    {
5411 			frame_new_width(frp, frp->fr_width - take,
5412 								FALSE, FALSE);
5413 			take = 0;
5414 		    }
5415 		}
5416 		if (run == 0)
5417 		    frp = frp->fr_next;
5418 		else
5419 		    frp = frp->fr_prev;
5420 	    }
5421 	}
5422     }
5423 }
5424 
5425 /*
5426  * Check 'winminheight' for a valid value and reduce it if needed.
5427  */
5428     void
5429 win_setminheight(void)
5430 {
5431     int		room;
5432     int		needed;
5433     int		first = TRUE;
5434 
5435     // loop until there is a 'winminheight' that is possible
5436     while (p_wmh > 0)
5437     {
5438 	room = Rows - p_ch;
5439 	needed = frame_minheight(topframe, NULL);
5440 	if (room >= needed)
5441 	    break;
5442 	--p_wmh;
5443 	if (first)
5444 	{
5445 	    emsg(_(e_noroom));
5446 	    first = FALSE;
5447 	}
5448     }
5449 }
5450 
5451 /*
5452  * Check 'winminwidth' for a valid value and reduce it if needed.
5453  */
5454     void
5455 win_setminwidth(void)
5456 {
5457     int		room;
5458     int		needed;
5459     int		first = TRUE;
5460 
5461     // loop until there is a 'winminheight' that is possible
5462     while (p_wmw > 0)
5463     {
5464 	room = Columns;
5465 	needed = frame_minwidth(topframe, NULL);
5466 	if (room >= needed)
5467 	    break;
5468 	--p_wmw;
5469 	if (first)
5470 	{
5471 	    emsg(_(e_noroom));
5472 	    first = FALSE;
5473 	}
5474     }
5475 }
5476 
5477 #if defined(FEAT_MOUSE) || defined(PROTO)
5478 
5479 /*
5480  * Status line of dragwin is dragged "offset" lines down (negative is up).
5481  */
5482     void
5483 win_drag_status_line(win_T *dragwin, int offset)
5484 {
5485     frame_T	*curfr;
5486     frame_T	*fr;
5487     int		room;
5488     int		row;
5489     int		up;	/* if TRUE, drag status line up, otherwise down */
5490     int		n;
5491 
5492     fr = dragwin->w_frame;
5493     curfr = fr;
5494     if (fr != topframe)		/* more than one window */
5495     {
5496 	fr = fr->fr_parent;
5497 	/* When the parent frame is not a column of frames, its parent should
5498 	 * be. */
5499 	if (fr->fr_layout != FR_COL)
5500 	{
5501 	    curfr = fr;
5502 	    if (fr != topframe)	/* only a row of windows, may drag statusline */
5503 		fr = fr->fr_parent;
5504 	}
5505     }
5506 
5507     /* If this is the last frame in a column, may want to resize the parent
5508      * frame instead (go two up to skip a row of frames). */
5509     while (curfr != topframe && curfr->fr_next == NULL)
5510     {
5511 	if (fr != topframe)
5512 	    fr = fr->fr_parent;
5513 	curfr = fr;
5514 	if (fr != topframe)
5515 	    fr = fr->fr_parent;
5516     }
5517 
5518     if (offset < 0) /* drag up */
5519     {
5520 	up = TRUE;
5521 	offset = -offset;
5522 	/* sum up the room of the current frame and above it */
5523 	if (fr == curfr)
5524 	{
5525 	    /* only one window */
5526 	    room = fr->fr_height - frame_minheight(fr, NULL);
5527 	}
5528 	else
5529 	{
5530 	    room = 0;
5531 	    for (fr = fr->fr_child; ; fr = fr->fr_next)
5532 	    {
5533 		room += fr->fr_height - frame_minheight(fr, NULL);
5534 		if (fr == curfr)
5535 		    break;
5536 	    }
5537 	}
5538 	fr = curfr->fr_next;		/* put fr at frame that grows */
5539     }
5540     else    /* drag down */
5541     {
5542 	up = FALSE;
5543 	/*
5544 	 * Only dragging the last status line can reduce p_ch.
5545 	 */
5546 	room = Rows - cmdline_row;
5547 	if (curfr->fr_next == NULL)
5548 	    room -= 1;
5549 	else
5550 	    room -= p_ch;
5551 	if (room < 0)
5552 	    room = 0;
5553 	/* sum up the room of frames below of the current one */
5554 	FOR_ALL_FRAMES(fr, curfr->fr_next)
5555 	    room += fr->fr_height - frame_minheight(fr, NULL);
5556 	fr = curfr;			/* put fr at window that grows */
5557     }
5558 
5559     if (room < offset)		/* Not enough room */
5560 	offset = room;		/* Move as far as we can */
5561     if (offset <= 0)
5562 	return;
5563 
5564     /*
5565      * Grow frame fr by "offset" lines.
5566      * Doesn't happen when dragging the last status line up.
5567      */
5568     if (fr != NULL)
5569 	frame_new_height(fr, fr->fr_height + offset, up, FALSE);
5570 
5571     if (up)
5572 	fr = curfr;		/* current frame gets smaller */
5573     else
5574 	fr = curfr->fr_next;	/* next frame gets smaller */
5575 
5576     /*
5577      * Now make the other frames smaller.
5578      */
5579     while (fr != NULL && offset > 0)
5580     {
5581 	n = frame_minheight(fr, NULL);
5582 	if (fr->fr_height - offset <= n)
5583 	{
5584 	    offset -= fr->fr_height - n;
5585 	    frame_new_height(fr, n, !up, FALSE);
5586 	}
5587 	else
5588 	{
5589 	    frame_new_height(fr, fr->fr_height - offset, !up, FALSE);
5590 	    break;
5591 	}
5592 	if (up)
5593 	    fr = fr->fr_prev;
5594 	else
5595 	    fr = fr->fr_next;
5596     }
5597     row = win_comp_pos();
5598     screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
5599     cmdline_row = row;
5600     p_ch = Rows - cmdline_row;
5601     if (p_ch < 1)
5602 	p_ch = 1;
5603     curtab->tp_ch_used = p_ch;
5604     redraw_all_later(SOME_VALID);
5605     showmode();
5606 }
5607 
5608 /*
5609  * Separator line of dragwin is dragged "offset" lines right (negative is left).
5610  */
5611     void
5612 win_drag_vsep_line(win_T *dragwin, int offset)
5613 {
5614     frame_T	*curfr;
5615     frame_T	*fr;
5616     int		room;
5617     int		left;	/* if TRUE, drag separator line left, otherwise right */
5618     int		n;
5619 
5620     fr = dragwin->w_frame;
5621     if (fr == topframe)		/* only one window (cannot happen?) */
5622 	return;
5623     curfr = fr;
5624     fr = fr->fr_parent;
5625     /* When the parent frame is not a row of frames, its parent should be. */
5626     if (fr->fr_layout != FR_ROW)
5627     {
5628 	if (fr == topframe)	/* only a column of windows (cannot happen?) */
5629 	    return;
5630 	curfr = fr;
5631 	fr = fr->fr_parent;
5632     }
5633 
5634     /* If this is the last frame in a row, may want to resize a parent
5635      * frame instead. */
5636     while (curfr->fr_next == NULL)
5637     {
5638 	if (fr == topframe)
5639 	    break;
5640 	curfr = fr;
5641 	fr = fr->fr_parent;
5642 	if (fr != topframe)
5643 	{
5644 	    curfr = fr;
5645 	    fr = fr->fr_parent;
5646 	}
5647     }
5648 
5649     if (offset < 0) /* drag left */
5650     {
5651 	left = TRUE;
5652 	offset = -offset;
5653 	/* sum up the room of the current frame and left of it */
5654 	room = 0;
5655 	for (fr = fr->fr_child; ; fr = fr->fr_next)
5656 	{
5657 	    room += fr->fr_width - frame_minwidth(fr, NULL);
5658 	    if (fr == curfr)
5659 		break;
5660 	}
5661 	fr = curfr->fr_next;		/* put fr at frame that grows */
5662     }
5663     else    /* drag right */
5664     {
5665 	left = FALSE;
5666 	/* sum up the room of frames right of the current one */
5667 	room = 0;
5668 	FOR_ALL_FRAMES(fr, curfr->fr_next)
5669 	    room += fr->fr_width - frame_minwidth(fr, NULL);
5670 	fr = curfr;			/* put fr at window that grows */
5671     }
5672 
5673     if (room < offset)		/* Not enough room */
5674 	offset = room;		/* Move as far as we can */
5675     if (offset <= 0)		/* No room at all, quit. */
5676 	return;
5677     if (fr == NULL)
5678 	return;			/* Safety check, should not happen. */
5679 
5680     /* grow frame fr by offset lines */
5681     frame_new_width(fr, fr->fr_width + offset, left, FALSE);
5682 
5683     /* shrink other frames: current and at the left or at the right */
5684     if (left)
5685 	fr = curfr;		/* current frame gets smaller */
5686     else
5687 	fr = curfr->fr_next;	/* next frame gets smaller */
5688 
5689     while (fr != NULL && offset > 0)
5690     {
5691 	n = frame_minwidth(fr, NULL);
5692 	if (fr->fr_width - offset <= n)
5693 	{
5694 	    offset -= fr->fr_width - n;
5695 	    frame_new_width(fr, n, !left, FALSE);
5696 	}
5697 	else
5698 	{
5699 	    frame_new_width(fr, fr->fr_width - offset, !left, FALSE);
5700 	    break;
5701 	}
5702 	if (left)
5703 	    fr = fr->fr_prev;
5704 	else
5705 	    fr = fr->fr_next;
5706     }
5707     (void)win_comp_pos();
5708     redraw_all_later(NOT_VALID);
5709 }
5710 #endif /* FEAT_MOUSE */
5711 
5712 #define FRACTION_MULT	16384L
5713 
5714 /*
5715  * Set wp->w_fraction for the current w_wrow and w_height.
5716  * Has no effect when the window is less than two lines.
5717  */
5718     void
5719 set_fraction(win_T *wp)
5720 {
5721     if (wp->w_height > 1)
5722 	wp->w_fraction = ((long)wp->w_wrow * FRACTION_MULT
5723 				    + wp->w_height / 2) / (long)wp->w_height;
5724 }
5725 
5726 /*
5727  * Set the height of a window.
5728  * "height" excludes any window toolbar.
5729  * This takes care of the things inside the window, not what happens to the
5730  * window position, the frame or to other windows.
5731  */
5732     void
5733 win_new_height(win_T *wp, int height)
5734 {
5735     int		prev_height = wp->w_height;
5736 
5737     /* Don't want a negative height.  Happens when splitting a tiny window.
5738      * Will equalize heights soon to fix it. */
5739     if (height < 0)
5740 	height = 0;
5741     if (wp->w_height == height)
5742 	return;	    /* nothing to do */
5743 
5744     if (wp->w_height > 0)
5745     {
5746 	if (wp == curwin)
5747 	    /* w_wrow needs to be valid. When setting 'laststatus' this may
5748 	     * call win_new_height() recursively. */
5749 	    validate_cursor();
5750 	if (wp->w_height != prev_height)
5751 	    return;  /* Recursive call already changed the size, bail out here
5752 			to avoid the following to mess things up. */
5753 	if (wp->w_wrow != wp->w_prev_fraction_row)
5754 	    set_fraction(wp);
5755     }
5756 
5757     wp->w_height = height;
5758     wp->w_skipcol = 0;
5759 
5760     /* There is no point in adjusting the scroll position when exiting.  Some
5761      * values might be invalid. */
5762     if (!exiting)
5763 	scroll_to_fraction(wp, prev_height);
5764 }
5765 
5766     void
5767 scroll_to_fraction(win_T *wp, int prev_height)
5768 {
5769     linenr_T	lnum;
5770     int		sline, line_size;
5771     int		height = wp->w_height;
5772 
5773     /* Don't change w_topline when height is zero.  Don't set w_topline when
5774      * 'scrollbind' is set and this isn't the current window. */
5775     if (height > 0 && (!wp->w_p_scb || wp == curwin))
5776     {
5777 	/*
5778 	 * Find a value for w_topline that shows the cursor at the same
5779 	 * relative position in the window as before (more or less).
5780 	 */
5781 	lnum = wp->w_cursor.lnum;
5782 	if (lnum < 1)		/* can happen when starting up */
5783 	    lnum = 1;
5784 	wp->w_wrow = ((long)wp->w_fraction * (long)height - 1L
5785 					 + FRACTION_MULT / 2) / FRACTION_MULT;
5786 	line_size = plines_win_col(wp, lnum, (long)(wp->w_cursor.col)) - 1;
5787 	sline = wp->w_wrow - line_size;
5788 
5789 	if (sline >= 0)
5790 	{
5791 	    /* Make sure the whole cursor line is visible, if possible. */
5792 	    int rows = plines_win(wp, lnum, FALSE);
5793 
5794 	    if (sline > wp->w_height - rows)
5795 	    {
5796 		sline = wp->w_height - rows;
5797 		wp->w_wrow -= rows - line_size;
5798 	    }
5799 	}
5800 
5801 	if (sline < 0)
5802 	{
5803 	    /*
5804 	     * Cursor line would go off top of screen if w_wrow was this high.
5805 	     * Make cursor line the first line in the window.  If not enough
5806 	     * room use w_skipcol;
5807 	     */
5808 	    wp->w_wrow = line_size;
5809 	    if (wp->w_wrow >= wp->w_height
5810 				       && (wp->w_width - win_col_off(wp)) > 0)
5811 	    {
5812 		wp->w_skipcol += wp->w_width - win_col_off(wp);
5813 		--wp->w_wrow;
5814 		while (wp->w_wrow >= wp->w_height)
5815 		{
5816 		    wp->w_skipcol += wp->w_width - win_col_off(wp)
5817 							   + win_col_off2(wp);
5818 		    --wp->w_wrow;
5819 		}
5820 	    }
5821 	    set_topline(wp, lnum);
5822 	}
5823 	else if (sline > 0)
5824 	{
5825 	    while (sline > 0 && lnum > 1)
5826 	    {
5827 #ifdef FEAT_FOLDING
5828 		hasFoldingWin(wp, lnum, &lnum, NULL, TRUE, NULL);
5829 		if (lnum == 1)
5830 		{
5831 		    /* first line in buffer is folded */
5832 		    line_size = 1;
5833 		    --sline;
5834 		    break;
5835 		}
5836 #endif
5837 		--lnum;
5838 #ifdef FEAT_DIFF
5839 		if (lnum == wp->w_topline)
5840 		    line_size = plines_win_nofill(wp, lnum, TRUE)
5841 							      + wp->w_topfill;
5842 		else
5843 #endif
5844 		    line_size = plines_win(wp, lnum, TRUE);
5845 		sline -= line_size;
5846 	    }
5847 
5848 	    if (sline < 0)
5849 	    {
5850 		/*
5851 		 * Line we want at top would go off top of screen.  Use next
5852 		 * line instead.
5853 		 */
5854 #ifdef FEAT_FOLDING
5855 		hasFoldingWin(wp, lnum, NULL, &lnum, TRUE, NULL);
5856 #endif
5857 		lnum++;
5858 		wp->w_wrow -= line_size + sline;
5859 	    }
5860 	    else if (sline > 0)
5861 	    {
5862 		/* First line of file reached, use that as topline. */
5863 		lnum = 1;
5864 		wp->w_wrow -= sline;
5865 	    }
5866 
5867 	    set_topline(wp, lnum);
5868 	}
5869     }
5870 
5871     if (wp == curwin)
5872     {
5873 	if (get_scrolloff_value())
5874 	    update_topline();
5875 	curs_columns(FALSE);	/* validate w_wrow */
5876     }
5877     if (prev_height > 0)
5878 	wp->w_prev_fraction_row = wp->w_wrow;
5879 
5880     win_comp_scroll(wp);
5881     redraw_win_later(wp, SOME_VALID);
5882     wp->w_redr_status = TRUE;
5883     invalidate_botline_win(wp);
5884 }
5885 
5886 /*
5887  * Set the width of a window.
5888  */
5889     void
5890 win_new_width(win_T *wp, int width)
5891 {
5892     wp->w_width = width;
5893     wp->w_lines_valid = 0;
5894     changed_line_abv_curs_win(wp);
5895     invalidate_botline_win(wp);
5896     if (wp == curwin)
5897     {
5898 	update_topline();
5899 	curs_columns(TRUE);	/* validate w_wrow */
5900     }
5901     redraw_win_later(wp, NOT_VALID);
5902     wp->w_redr_status = TRUE;
5903 }
5904 
5905     void
5906 win_comp_scroll(win_T *wp)
5907 {
5908     wp->w_p_scr = ((unsigned)wp->w_height >> 1);
5909     if (wp->w_p_scr == 0)
5910 	wp->w_p_scr = 1;
5911 }
5912 
5913 /*
5914  * command_height: called whenever p_ch has been changed
5915  */
5916     void
5917 command_height(void)
5918 {
5919     int		h;
5920     frame_T	*frp;
5921     int		old_p_ch = curtab->tp_ch_used;
5922 
5923     /* Use the value of p_ch that we remembered.  This is needed for when the
5924      * GUI starts up, we can't be sure in what order things happen.  And when
5925      * p_ch was changed in another tab page. */
5926     curtab->tp_ch_used = p_ch;
5927 
5928     /* Find bottom frame with width of screen. */
5929     frp = lastwin->w_frame;
5930     while (frp->fr_width != Columns && frp->fr_parent != NULL)
5931 	frp = frp->fr_parent;
5932 
5933     /* Avoid changing the height of a window with 'winfixheight' set. */
5934     while (frp->fr_prev != NULL && frp->fr_layout == FR_LEAF
5935 						      && frp->fr_win->w_p_wfh)
5936 	frp = frp->fr_prev;
5937 
5938     if (starting != NO_SCREEN)
5939     {
5940 	cmdline_row = Rows - p_ch;
5941 
5942 	if (p_ch > old_p_ch)		    /* p_ch got bigger */
5943 	{
5944 	    while (p_ch > old_p_ch)
5945 	    {
5946 		if (frp == NULL)
5947 		{
5948 		    emsg(_(e_noroom));
5949 		    p_ch = old_p_ch;
5950 		    curtab->tp_ch_used = p_ch;
5951 		    cmdline_row = Rows - p_ch;
5952 		    break;
5953 		}
5954 		h = frp->fr_height - frame_minheight(frp, NULL);
5955 		if (h > p_ch - old_p_ch)
5956 		    h = p_ch - old_p_ch;
5957 		old_p_ch += h;
5958 		frame_add_height(frp, -h);
5959 		frp = frp->fr_prev;
5960 	    }
5961 
5962 	    /* Recompute window positions. */
5963 	    (void)win_comp_pos();
5964 
5965 	    /* clear the lines added to cmdline */
5966 	    if (full_screen)
5967 		screen_fill((int)(cmdline_row), (int)Rows, 0,
5968 						   (int)Columns, ' ', ' ', 0);
5969 	    msg_row = cmdline_row;
5970 	    redraw_cmdline = TRUE;
5971 	    return;
5972 	}
5973 
5974 	if (msg_row < cmdline_row)
5975 	    msg_row = cmdline_row;
5976 	redraw_cmdline = TRUE;
5977     }
5978     frame_add_height(frp, (int)(old_p_ch - p_ch));
5979 
5980     /* Recompute window positions. */
5981     if (frp != lastwin->w_frame)
5982 	(void)win_comp_pos();
5983 }
5984 
5985 /*
5986  * Resize frame "frp" to be "n" lines higher (negative for less high).
5987  * Also resize the frames it is contained in.
5988  */
5989     static void
5990 frame_add_height(frame_T *frp, int n)
5991 {
5992     frame_new_height(frp, frp->fr_height + n, FALSE, FALSE);
5993     for (;;)
5994     {
5995 	frp = frp->fr_parent;
5996 	if (frp == NULL)
5997 	    break;
5998 	frp->fr_height += n;
5999     }
6000 }
6001 
6002 /*
6003  * Add or remove a status line for the bottom window(s), according to the
6004  * value of 'laststatus'.
6005  */
6006     void
6007 last_status(
6008     int		morewin)	/* pretend there are two or more windows */
6009 {
6010     /* Don't make a difference between horizontal or vertical split. */
6011     last_status_rec(topframe, (p_ls == 2
6012 			  || (p_ls == 1 && (morewin || !ONE_WINDOW))));
6013 }
6014 
6015     static void
6016 last_status_rec(frame_T *fr, int statusline)
6017 {
6018     frame_T	*fp;
6019     win_T	*wp;
6020 
6021     if (fr->fr_layout == FR_LEAF)
6022     {
6023 	wp = fr->fr_win;
6024 	if (wp->w_status_height != 0 && !statusline)
6025 	{
6026 	    /* remove status line */
6027 	    win_new_height(wp, wp->w_height + 1);
6028 	    wp->w_status_height = 0;
6029 	    comp_col();
6030 	}
6031 	else if (wp->w_status_height == 0 && statusline)
6032 	{
6033 	    /* Find a frame to take a line from. */
6034 	    fp = fr;
6035 	    while (fp->fr_height <= frame_minheight(fp, NULL))
6036 	    {
6037 		if (fp == topframe)
6038 		{
6039 		    emsg(_(e_noroom));
6040 		    return;
6041 		}
6042 		/* In a column of frames: go to frame above.  If already at
6043 		 * the top or in a row of frames: go to parent. */
6044 		if (fp->fr_parent->fr_layout == FR_COL && fp->fr_prev != NULL)
6045 		    fp = fp->fr_prev;
6046 		else
6047 		    fp = fp->fr_parent;
6048 	    }
6049 	    wp->w_status_height = 1;
6050 	    if (fp != fr)
6051 	    {
6052 		frame_new_height(fp, fp->fr_height - 1, FALSE, FALSE);
6053 		frame_fix_height(wp);
6054 		(void)win_comp_pos();
6055 	    }
6056 	    else
6057 		win_new_height(wp, wp->w_height - 1);
6058 	    comp_col();
6059 	    redraw_all_later(SOME_VALID);
6060 	}
6061     }
6062     else if (fr->fr_layout == FR_ROW)
6063     {
6064 	/* vertically split windows, set status line for each one */
6065 	FOR_ALL_FRAMES(fp, fr->fr_child)
6066 	    last_status_rec(fp, statusline);
6067     }
6068     else
6069     {
6070 	/* horizontally split window, set status line for last one */
6071 	for (fp = fr->fr_child; fp->fr_next != NULL; fp = fp->fr_next)
6072 	    ;
6073 	last_status_rec(fp, statusline);
6074     }
6075 }
6076 
6077 /*
6078  * Return the number of lines used by the tab page line.
6079  */
6080     int
6081 tabline_height(void)
6082 {
6083 #ifdef FEAT_GUI_TABLINE
6084     /* When the GUI has the tabline then this always returns zero. */
6085     if (gui_use_tabline())
6086 	return 0;
6087 #endif
6088     switch (p_stal)
6089     {
6090 	case 0: return 0;
6091 	case 1: return (first_tabpage->tp_next == NULL) ? 0 : 1;
6092     }
6093     return 1;
6094 }
6095 
6096 /*
6097  * Return the minimal number of rows that is needed on the screen to display
6098  * the current number of windows.
6099  */
6100     int
6101 min_rows(void)
6102 {
6103     int		total;
6104     tabpage_T	*tp;
6105     int		n;
6106 
6107     if (firstwin == NULL)	/* not initialized yet */
6108 	return MIN_LINES;
6109 
6110     total = 0;
6111     FOR_ALL_TABPAGES(tp)
6112     {
6113 	n = frame_minheight(tp->tp_topframe, NULL);
6114 	if (total < n)
6115 	    total = n;
6116     }
6117     total += tabline_height();
6118     total += 1;		/* count the room for the command line */
6119     return total;
6120 }
6121 
6122 /*
6123  * Return TRUE if there is only one window (in the current tab page), not
6124  * counting a help or preview window, unless it is the current window.
6125  * Does not count "aucmd_win".
6126  */
6127     int
6128 only_one_window(void)
6129 {
6130     int		count = 0;
6131     win_T	*wp;
6132 
6133     /* If there is another tab page there always is another window. */
6134     if (first_tabpage->tp_next != NULL)
6135 	return FALSE;
6136 
6137     FOR_ALL_WINDOWS(wp)
6138 	if (wp->w_buffer != NULL
6139 		&& (!((bt_help(wp->w_buffer) && !bt_help(curbuf))
6140 # ifdef FEAT_QUICKFIX
6141 		    || wp->w_p_pvw
6142 # endif
6143 	     ) || wp == curwin) && wp != aucmd_win)
6144 	    ++count;
6145     return (count <= 1);
6146 }
6147 
6148 /*
6149  * Correct the cursor line number in other windows.  Used after changing the
6150  * current buffer, and before applying autocommands.
6151  * When "do_curwin" is TRUE, also check current window.
6152  */
6153     void
6154 check_lnums(int do_curwin)
6155 {
6156     win_T	*wp;
6157     tabpage_T	*tp;
6158 
6159     FOR_ALL_TAB_WINDOWS(tp, wp)
6160 	if ((do_curwin || wp != curwin) && wp->w_buffer == curbuf)
6161 	{
6162 	    if (wp->w_cursor.lnum > curbuf->b_ml.ml_line_count)
6163 		wp->w_cursor.lnum = curbuf->b_ml.ml_line_count;
6164 	    if (wp->w_topline > curbuf->b_ml.ml_line_count)
6165 		wp->w_topline = curbuf->b_ml.ml_line_count;
6166 	}
6167 }
6168 
6169 /*
6170  * A snapshot of the window sizes, to restore them after closing the help
6171  * window.
6172  * Only these fields are used:
6173  * fr_layout
6174  * fr_width
6175  * fr_height
6176  * fr_next
6177  * fr_child
6178  * fr_win (only valid for the old curwin, NULL otherwise)
6179  */
6180 
6181 /*
6182  * Create a snapshot of the current frame sizes.
6183  */
6184     void
6185 make_snapshot(int idx)
6186 {
6187     clear_snapshot(curtab, idx);
6188     make_snapshot_rec(topframe, &curtab->tp_snapshot[idx]);
6189 }
6190 
6191     static void
6192 make_snapshot_rec(frame_T *fr, frame_T **frp)
6193 {
6194     *frp = (frame_T *)alloc_clear((unsigned)sizeof(frame_T));
6195     if (*frp == NULL)
6196 	return;
6197     (*frp)->fr_layout = fr->fr_layout;
6198     (*frp)->fr_width = fr->fr_width;
6199     (*frp)->fr_height = fr->fr_height;
6200     if (fr->fr_next != NULL)
6201 	make_snapshot_rec(fr->fr_next, &((*frp)->fr_next));
6202     if (fr->fr_child != NULL)
6203 	make_snapshot_rec(fr->fr_child, &((*frp)->fr_child));
6204     if (fr->fr_layout == FR_LEAF && fr->fr_win == curwin)
6205 	(*frp)->fr_win = curwin;
6206 }
6207 
6208 /*
6209  * Remove any existing snapshot.
6210  */
6211     static void
6212 clear_snapshot(tabpage_T *tp, int idx)
6213 {
6214     clear_snapshot_rec(tp->tp_snapshot[idx]);
6215     tp->tp_snapshot[idx] = NULL;
6216 }
6217 
6218     static void
6219 clear_snapshot_rec(frame_T *fr)
6220 {
6221     if (fr != NULL)
6222     {
6223 	clear_snapshot_rec(fr->fr_next);
6224 	clear_snapshot_rec(fr->fr_child);
6225 	vim_free(fr);
6226     }
6227 }
6228 
6229 /*
6230  * Restore a previously created snapshot, if there is any.
6231  * This is only done if the screen size didn't change and the window layout is
6232  * still the same.
6233  */
6234     void
6235 restore_snapshot(
6236     int		idx,
6237     int		close_curwin)	    /* closing current window */
6238 {
6239     win_T	*wp;
6240 
6241     if (curtab->tp_snapshot[idx] != NULL
6242 	    && curtab->tp_snapshot[idx]->fr_width == topframe->fr_width
6243 	    && curtab->tp_snapshot[idx]->fr_height == topframe->fr_height
6244 	    && check_snapshot_rec(curtab->tp_snapshot[idx], topframe) == OK)
6245     {
6246 	wp = restore_snapshot_rec(curtab->tp_snapshot[idx], topframe);
6247 	win_comp_pos();
6248 	if (wp != NULL && close_curwin)
6249 	    win_goto(wp);
6250 	redraw_all_later(NOT_VALID);
6251     }
6252     clear_snapshot(curtab, idx);
6253 }
6254 
6255 /*
6256  * Check if frames "sn" and "fr" have the same layout, same following frames
6257  * and same children.  And the window pointer is valid.
6258  */
6259     static int
6260 check_snapshot_rec(frame_T *sn, frame_T *fr)
6261 {
6262     if (sn->fr_layout != fr->fr_layout
6263 	    || (sn->fr_next == NULL) != (fr->fr_next == NULL)
6264 	    || (sn->fr_child == NULL) != (fr->fr_child == NULL)
6265 	    || (sn->fr_next != NULL
6266 		&& check_snapshot_rec(sn->fr_next, fr->fr_next) == FAIL)
6267 	    || (sn->fr_child != NULL
6268 		&& check_snapshot_rec(sn->fr_child, fr->fr_child) == FAIL)
6269 	    || (sn->fr_win != NULL && !win_valid(sn->fr_win)))
6270 	return FAIL;
6271     return OK;
6272 }
6273 
6274 /*
6275  * Copy the size of snapshot frame "sn" to frame "fr".  Do the same for all
6276  * following frames and children.
6277  * Returns a pointer to the old current window, or NULL.
6278  */
6279     static win_T *
6280 restore_snapshot_rec(frame_T *sn, frame_T *fr)
6281 {
6282     win_T	*wp = NULL;
6283     win_T	*wp2;
6284 
6285     fr->fr_height = sn->fr_height;
6286     fr->fr_width = sn->fr_width;
6287     if (fr->fr_layout == FR_LEAF)
6288     {
6289 	frame_new_height(fr, fr->fr_height, FALSE, FALSE);
6290 	frame_new_width(fr, fr->fr_width, FALSE, FALSE);
6291 	wp = sn->fr_win;
6292     }
6293     if (sn->fr_next != NULL)
6294     {
6295 	wp2 = restore_snapshot_rec(sn->fr_next, fr->fr_next);
6296 	if (wp2 != NULL)
6297 	    wp = wp2;
6298     }
6299     if (sn->fr_child != NULL)
6300     {
6301 	wp2 = restore_snapshot_rec(sn->fr_child, fr->fr_child);
6302 	if (wp2 != NULL)
6303 	    wp = wp2;
6304     }
6305     return wp;
6306 }
6307 
6308 #if defined(FEAT_EVAL) || defined(FEAT_PYTHON) || defined(FEAT_PYTHON3) \
6309 	|| defined(PROTO)
6310 /*
6311  * Set "win" to be the curwin and "tp" to be the current tab page.
6312  * restore_win() MUST be called to undo, also when FAIL is returned.
6313  * No autocommands will be executed until restore_win() is called.
6314  * When "no_display" is TRUE the display won't be affected, no redraw is
6315  * triggered, another tabpage access is limited.
6316  * Returns FAIL if switching to "win" failed.
6317  */
6318     int
6319 switch_win(
6320     win_T	**save_curwin,
6321     tabpage_T	**save_curtab,
6322     win_T	*win,
6323     tabpage_T	*tp,
6324     int		no_display)
6325 {
6326     block_autocmds();
6327     *save_curwin = curwin;
6328     if (tp != NULL)
6329     {
6330 	*save_curtab = curtab;
6331 	if (no_display)
6332 	{
6333 	    curtab->tp_firstwin = firstwin;
6334 	    curtab->tp_lastwin = lastwin;
6335 	    curtab = tp;
6336 	    firstwin = curtab->tp_firstwin;
6337 	    lastwin = curtab->tp_lastwin;
6338 	}
6339 	else
6340 	    goto_tabpage_tp(tp, FALSE, FALSE);
6341     }
6342     if (!win_valid(win))
6343 	return FAIL;
6344     curwin = win;
6345     curbuf = curwin->w_buffer;
6346     return OK;
6347 }
6348 
6349 /*
6350  * Restore current tabpage and window saved by switch_win(), if still valid.
6351  * When "no_display" is TRUE the display won't be affected, no redraw is
6352  * triggered.
6353  */
6354     void
6355 restore_win(
6356     win_T	*save_curwin UNUSED,
6357     tabpage_T	*save_curtab UNUSED,
6358     int		no_display UNUSED)
6359 {
6360     if (save_curtab != NULL && valid_tabpage(save_curtab))
6361     {
6362 	if (no_display)
6363 	{
6364 	    curtab->tp_firstwin = firstwin;
6365 	    curtab->tp_lastwin = lastwin;
6366 	    curtab = save_curtab;
6367 	    firstwin = curtab->tp_firstwin;
6368 	    lastwin = curtab->tp_lastwin;
6369 	}
6370 	else
6371 	    goto_tabpage_tp(save_curtab, FALSE, FALSE);
6372     }
6373     if (win_valid(save_curwin))
6374     {
6375 	curwin = save_curwin;
6376 	curbuf = curwin->w_buffer;
6377     }
6378     unblock_autocmds();
6379 }
6380 
6381 /*
6382  * Make "buf" the current buffer.  restore_buffer() MUST be called to undo.
6383  * No autocommands will be executed.  Use aucmd_prepbuf() if there are any.
6384  */
6385     void
6386 switch_buffer(bufref_T *save_curbuf, buf_T *buf)
6387 {
6388     block_autocmds();
6389     set_bufref(save_curbuf, curbuf);
6390     --curbuf->b_nwindows;
6391     curbuf = buf;
6392     curwin->w_buffer = buf;
6393     ++curbuf->b_nwindows;
6394 }
6395 
6396 /*
6397  * Restore the current buffer after using switch_buffer().
6398  */
6399     void
6400 restore_buffer(bufref_T *save_curbuf)
6401 {
6402     unblock_autocmds();
6403     /* Check for valid buffer, just in case. */
6404     if (bufref_valid(save_curbuf))
6405     {
6406 	--curbuf->b_nwindows;
6407 	curwin->w_buffer = save_curbuf->br_buf;
6408 	curbuf = save_curbuf->br_buf;
6409 	++curbuf->b_nwindows;
6410     }
6411 }
6412 #endif
6413 
6414 #if defined(FEAT_GUI) || defined(PROTO)
6415 /*
6416  * Return TRUE if there is any vertically split window.
6417  */
6418     int
6419 win_hasvertsplit(void)
6420 {
6421     frame_T	*fr;
6422 
6423     if (topframe->fr_layout == FR_ROW)
6424 	return TRUE;
6425 
6426     if (topframe->fr_layout == FR_COL)
6427 	FOR_ALL_FRAMES(fr, topframe->fr_child)
6428 	    if (fr->fr_layout == FR_ROW)
6429 		return TRUE;
6430 
6431     return FALSE;
6432 }
6433 #endif
6434 
6435 #if defined(FEAT_SEARCH_EXTRA) || defined(PROTO)
6436 /*
6437  * Add match to the match list of window 'wp'.  The pattern 'pat' will be
6438  * highlighted with the group 'grp' with priority 'prio'.
6439  * Optionally, a desired ID 'id' can be specified (greater than or equal to 1).
6440  * If no particular ID is desired, -1 must be specified for 'id'.
6441  * Return ID of added match, -1 on failure.
6442  */
6443     int
6444 match_add(
6445     win_T	*wp,
6446     char_u	*grp,
6447     char_u	*pat,
6448     int		prio,
6449     int		id,
6450     list_T	*pos_list,
6451     char_u      *conceal_char UNUSED) /* pointer to conceal replacement char */
6452 {
6453     matchitem_T	*cur;
6454     matchitem_T	*prev;
6455     matchitem_T	*m;
6456     int		hlg_id;
6457     regprog_T	*regprog = NULL;
6458     int		rtype = SOME_VALID;
6459 
6460     if (*grp == NUL || (pat != NULL && *pat == NUL))
6461 	return -1;
6462     if (id < -1 || id == 0)
6463     {
6464 	semsg(_("E799: Invalid ID: %d (must be greater than or equal to 1)"), id);
6465 	return -1;
6466     }
6467     if (id != -1)
6468     {
6469 	cur = wp->w_match_head;
6470 	while (cur != NULL)
6471 	{
6472 	    if (cur->id == id)
6473 	    {
6474 		semsg(_("E801: ID already taken: %d"), id);
6475 		return -1;
6476 	    }
6477 	    cur = cur->next;
6478 	}
6479     }
6480     if ((hlg_id = syn_namen2id(grp, (int)STRLEN(grp))) == 0)
6481     {
6482 	semsg(_(e_nogroup), grp);
6483 	return -1;
6484     }
6485     if (pat != NULL && (regprog = vim_regcomp(pat, RE_MAGIC)) == NULL)
6486     {
6487 	semsg(_(e_invarg2), pat);
6488 	return -1;
6489     }
6490 
6491     /* Find available match ID. */
6492     while (id == -1)
6493     {
6494 	cur = wp->w_match_head;
6495 	while (cur != NULL && cur->id != wp->w_next_match_id)
6496 	    cur = cur->next;
6497 	if (cur == NULL)
6498 	    id = wp->w_next_match_id;
6499 	wp->w_next_match_id++;
6500     }
6501 
6502     /* Build new match. */
6503     m = (matchitem_T *)alloc_clear(sizeof(matchitem_T));
6504     m->id = id;
6505     m->priority = prio;
6506     m->pattern = pat == NULL ? NULL : vim_strsave(pat);
6507     m->hlg_id = hlg_id;
6508     m->match.regprog = regprog;
6509     m->match.rmm_ic = FALSE;
6510     m->match.rmm_maxcol = 0;
6511 # if defined(FEAT_CONCEAL)
6512     m->conceal_char = 0;
6513     if (conceal_char != NULL)
6514 	m->conceal_char = (*mb_ptr2char)(conceal_char);
6515 # endif
6516 
6517     /* Set up position matches */
6518     if (pos_list != NULL)
6519     {
6520 	linenr_T	toplnum = 0;
6521 	linenr_T	botlnum = 0;
6522 	listitem_T	*li;
6523 	int		i;
6524 
6525 	for (i = 0, li = pos_list->lv_first; li != NULL && i < MAXPOSMATCH;
6526 							i++, li = li->li_next)
6527 	{
6528 	    linenr_T	lnum = 0;
6529 	    colnr_T	col = 0;
6530 	    int		len = 1;
6531 	    list_T	*subl;
6532 	    listitem_T	*subli;
6533 	    int		error = FALSE;
6534 
6535 	    if (li->li_tv.v_type == VAR_LIST)
6536 	    {
6537 		subl = li->li_tv.vval.v_list;
6538 		if (subl == NULL)
6539 		    goto fail;
6540 		subli = subl->lv_first;
6541 		if (subli == NULL)
6542 		    goto fail;
6543 		lnum = tv_get_number_chk(&subli->li_tv, &error);
6544 		if (error == TRUE)
6545 		    goto fail;
6546 		if (lnum == 0)
6547 		{
6548 		    --i;
6549 		    continue;
6550 		}
6551 		m->pos.pos[i].lnum = lnum;
6552 		subli = subli->li_next;
6553 		if (subli != NULL)
6554 		{
6555 		    col = tv_get_number_chk(&subli->li_tv, &error);
6556 		    if (error == TRUE)
6557 			goto fail;
6558 		    subli = subli->li_next;
6559 		    if (subli != NULL)
6560 		    {
6561 			len = tv_get_number_chk(&subli->li_tv, &error);
6562 			if (error == TRUE)
6563 			    goto fail;
6564 		    }
6565 		}
6566 		m->pos.pos[i].col = col;
6567 		m->pos.pos[i].len = len;
6568 	    }
6569 	    else if (li->li_tv.v_type == VAR_NUMBER)
6570 	    {
6571 		if (li->li_tv.vval.v_number == 0)
6572 		{
6573 		    --i;
6574 		    continue;
6575 		}
6576 		m->pos.pos[i].lnum = li->li_tv.vval.v_number;
6577 		m->pos.pos[i].col = 0;
6578 		m->pos.pos[i].len = 0;
6579 	    }
6580 	    else
6581 	    {
6582 		emsg(_("List or number required"));
6583 		goto fail;
6584 	    }
6585 	    if (toplnum == 0 || lnum < toplnum)
6586 		toplnum = lnum;
6587 	    if (botlnum == 0 || lnum >= botlnum)
6588 		botlnum = lnum + 1;
6589 	}
6590 
6591 	/* Calculate top and bottom lines for redrawing area */
6592 	if (toplnum != 0)
6593 	{
6594 	    if (wp->w_buffer->b_mod_set)
6595 	    {
6596 		if (wp->w_buffer->b_mod_top > toplnum)
6597 		    wp->w_buffer->b_mod_top = toplnum;
6598 		if (wp->w_buffer->b_mod_bot < botlnum)
6599 		    wp->w_buffer->b_mod_bot = botlnum;
6600 	    }
6601 	    else
6602 	    {
6603 		wp->w_buffer->b_mod_set = TRUE;
6604 		wp->w_buffer->b_mod_top = toplnum;
6605 		wp->w_buffer->b_mod_bot = botlnum;
6606 		wp->w_buffer->b_mod_xlines = 0;
6607 	    }
6608 	    m->pos.toplnum = toplnum;
6609 	    m->pos.botlnum = botlnum;
6610 	    rtype = VALID;
6611 	}
6612     }
6613 
6614     /* Insert new match.  The match list is in ascending order with regard to
6615      * the match priorities. */
6616     cur = wp->w_match_head;
6617     prev = cur;
6618     while (cur != NULL && prio >= cur->priority)
6619     {
6620 	prev = cur;
6621 	cur = cur->next;
6622     }
6623     if (cur == prev)
6624 	wp->w_match_head = m;
6625     else
6626 	prev->next = m;
6627     m->next = cur;
6628 
6629     redraw_later(rtype);
6630     return id;
6631 
6632 fail:
6633     vim_free(m);
6634     return -1;
6635 }
6636 
6637 /*
6638  * Delete match with ID 'id' in the match list of window 'wp'.
6639  * Print error messages if 'perr' is TRUE.
6640  */
6641     int
6642 match_delete(win_T *wp, int id, int perr)
6643 {
6644     matchitem_T	*cur = wp->w_match_head;
6645     matchitem_T	*prev = cur;
6646     int		rtype = SOME_VALID;
6647 
6648     if (id < 1)
6649     {
6650 	if (perr == TRUE)
6651 	    semsg(_("E802: Invalid ID: %d (must be greater than or equal to 1)"),
6652 									  id);
6653 	return -1;
6654     }
6655     while (cur != NULL && cur->id != id)
6656     {
6657 	prev = cur;
6658 	cur = cur->next;
6659     }
6660     if (cur == NULL)
6661     {
6662 	if (perr == TRUE)
6663 	    semsg(_("E803: ID not found: %d"), id);
6664 	return -1;
6665     }
6666     if (cur == prev)
6667 	wp->w_match_head = cur->next;
6668     else
6669 	prev->next = cur->next;
6670     vim_regfree(cur->match.regprog);
6671     vim_free(cur->pattern);
6672     if (cur->pos.toplnum != 0)
6673     {
6674 	if (wp->w_buffer->b_mod_set)
6675 	{
6676 	    if (wp->w_buffer->b_mod_top > cur->pos.toplnum)
6677 		wp->w_buffer->b_mod_top = cur->pos.toplnum;
6678 	    if (wp->w_buffer->b_mod_bot < cur->pos.botlnum)
6679 		wp->w_buffer->b_mod_bot = cur->pos.botlnum;
6680 	}
6681 	else
6682 	{
6683 	    wp->w_buffer->b_mod_set = TRUE;
6684 	    wp->w_buffer->b_mod_top = cur->pos.toplnum;
6685 	    wp->w_buffer->b_mod_bot = cur->pos.botlnum;
6686 	    wp->w_buffer->b_mod_xlines = 0;
6687 	}
6688 	rtype = VALID;
6689     }
6690     vim_free(cur);
6691     redraw_later(rtype);
6692     return 0;
6693 }
6694 
6695 /*
6696  * Delete all matches in the match list of window 'wp'.
6697  */
6698     void
6699 clear_matches(win_T *wp)
6700 {
6701     matchitem_T *m;
6702 
6703     while (wp->w_match_head != NULL)
6704     {
6705 	m = wp->w_match_head->next;
6706 	vim_regfree(wp->w_match_head->match.regprog);
6707 	vim_free(wp->w_match_head->pattern);
6708 	vim_free(wp->w_match_head);
6709 	wp->w_match_head = m;
6710     }
6711     redraw_later(SOME_VALID);
6712 }
6713 
6714 /*
6715  * Get match from ID 'id' in window 'wp'.
6716  * Return NULL if match not found.
6717  */
6718     matchitem_T *
6719 get_match(win_T *wp, int id)
6720 {
6721     matchitem_T *cur = wp->w_match_head;
6722 
6723     while (cur != NULL && cur->id != id)
6724 	cur = cur->next;
6725     return cur;
6726 }
6727 #endif
6728 
6729 #if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3) || defined(PROTO)
6730     int
6731 get_win_number(win_T *wp, win_T *first_win)
6732 {
6733     int		i = 1;
6734     win_T	*w;
6735 
6736     for (w = first_win; w != NULL && w != wp; w = W_NEXT(w))
6737 	++i;
6738 
6739     if (w == NULL)
6740 	return 0;
6741     else
6742 	return i;
6743 }
6744 
6745     int
6746 get_tab_number(tabpage_T *tp UNUSED)
6747 {
6748     int		i = 1;
6749     tabpage_T	*t;
6750 
6751     for (t = first_tabpage; t != NULL && t != tp; t = t->tp_next)
6752 	++i;
6753 
6754     if (t == NULL)
6755 	return 0;
6756     else
6757 	return i;
6758 }
6759 #endif
6760 
6761 /*
6762  * Return TRUE if "topfrp" and its children are at the right height.
6763  */
6764     static int
6765 frame_check_height(frame_T *topfrp, int height)
6766 {
6767     frame_T *frp;
6768 
6769     if (topfrp->fr_height != height)
6770 	return FALSE;
6771 
6772     if (topfrp->fr_layout == FR_ROW)
6773 	FOR_ALL_FRAMES(frp, topfrp->fr_child)
6774 	    if (frp->fr_height != height)
6775 		return FALSE;
6776 
6777     return TRUE;
6778 }
6779 
6780 /*
6781  * Return TRUE if "topfrp" and its children are at the right width.
6782  */
6783     static int
6784 frame_check_width(frame_T *topfrp, int width)
6785 {
6786     frame_T *frp;
6787 
6788     if (topfrp->fr_width != width)
6789 	return FALSE;
6790 
6791     if (topfrp->fr_layout == FR_COL)
6792 	FOR_ALL_FRAMES(frp, topfrp->fr_child)
6793 	    if (frp->fr_width != width)
6794 		return FALSE;
6795 
6796     return TRUE;
6797 }
6798 
6799 #if defined(FEAT_EVAL) || defined(PROTO)
6800     int
6801 win_getid(typval_T *argvars)
6802 {
6803     int	    winnr;
6804     win_T   *wp;
6805 
6806     if (argvars[0].v_type == VAR_UNKNOWN)
6807 	return curwin->w_id;
6808     winnr = tv_get_number(&argvars[0]);
6809     if (winnr > 0)
6810     {
6811 	if (argvars[1].v_type == VAR_UNKNOWN)
6812 	    wp = firstwin;
6813 	else
6814 	{
6815 	    tabpage_T	*tp;
6816 	    int		tabnr = tv_get_number(&argvars[1]);
6817 
6818 	    FOR_ALL_TABPAGES(tp)
6819 		if (--tabnr == 0)
6820 		    break;
6821 	    if (tp == NULL)
6822 		return -1;
6823 	    if (tp == curtab)
6824 		wp = firstwin;
6825 	    else
6826 		wp = tp->tp_firstwin;
6827 	}
6828 	for ( ; wp != NULL; wp = wp->w_next)
6829 	    if (--winnr == 0)
6830 		return wp->w_id;
6831     }
6832     return 0;
6833 }
6834 
6835     int
6836 win_gotoid(typval_T *argvars)
6837 {
6838     win_T	*wp;
6839     tabpage_T   *tp;
6840     int		id = tv_get_number(&argvars[0]);
6841 
6842     FOR_ALL_TAB_WINDOWS(tp, wp)
6843 	    if (wp->w_id == id)
6844 	    {
6845 		goto_tabpage_win(tp, wp);
6846 		return 1;
6847 	    }
6848     return 0;
6849 }
6850 
6851     void
6852 win_id2tabwin(typval_T *argvars, list_T *list)
6853 {
6854     win_T	*wp;
6855     tabpage_T   *tp;
6856     int		winnr = 1;
6857     int		tabnr = 1;
6858     int		id = tv_get_number(&argvars[0]);
6859 
6860     FOR_ALL_TABPAGES(tp)
6861     {
6862 	FOR_ALL_WINDOWS_IN_TAB(tp, wp)
6863 	{
6864 	    if (wp->w_id == id)
6865 	    {
6866 		list_append_number(list, tabnr);
6867 		list_append_number(list, winnr);
6868 		return;
6869 	    }
6870 	    ++winnr;
6871 	}
6872 	++tabnr;
6873 	winnr = 1;
6874     }
6875     list_append_number(list, 0);
6876     list_append_number(list, 0);
6877 }
6878 
6879     win_T *
6880 win_id2wp(int id)
6881 {
6882     win_T	*wp;
6883     tabpage_T   *tp;
6884 
6885     FOR_ALL_TAB_WINDOWS(tp, wp)
6886 	if (wp->w_id == id)
6887 	    return wp;
6888 
6889     return NULL;
6890 }
6891 
6892     int
6893 win_id2win(typval_T *argvars)
6894 {
6895     win_T   *wp;
6896     int	    nr = 1;
6897     int	    id = tv_get_number(&argvars[0]);
6898 
6899     FOR_ALL_WINDOWS(wp)
6900     {
6901 	if (wp->w_id == id)
6902 	    return nr;
6903 	++nr;
6904     }
6905     return 0;
6906 }
6907 
6908     void
6909 win_findbuf(typval_T *argvars, list_T *list)
6910 {
6911     win_T	*wp;
6912     tabpage_T   *tp;
6913     int		bufnr = tv_get_number(&argvars[0]);
6914 
6915     FOR_ALL_TAB_WINDOWS(tp, wp)
6916 	    if (wp->w_buffer->b_fnum == bufnr)
6917 		list_append_number(list, wp->w_id);
6918 }
6919 
6920 /*
6921  * Get the layout of the given tab page for winlayout().
6922  */
6923     void
6924 get_framelayout(frame_T *fr, list_T *l, int outer)
6925 {
6926     frame_T	*child;
6927     list_T	*fr_list;
6928     list_T	*win_list;
6929 
6930     if (fr == NULL)
6931 	return;
6932 
6933     if (outer)
6934 	// outermost call from f_winlayout()
6935 	fr_list = l;
6936     else
6937     {
6938 	fr_list = list_alloc();
6939 	if (fr_list == NULL)
6940 	    return;
6941 	list_append_list(l, fr_list);
6942     }
6943 
6944     if (fr->fr_layout == FR_LEAF)
6945     {
6946 	if (fr->fr_win != NULL)
6947 	{
6948 	    list_append_string(fr_list, (char_u *)"leaf", -1);
6949 	    list_append_number(fr_list, fr->fr_win->w_id);
6950 	}
6951     }
6952     else
6953     {
6954 	list_append_string(fr_list,
6955 	     fr->fr_layout == FR_ROW ?  (char_u *)"row" : (char_u *)"col", -1);
6956 
6957 	win_list = list_alloc();
6958 	if (win_list == NULL)
6959 	    return;
6960 	list_append_list(fr_list, win_list);
6961 	child = fr->fr_child;
6962 	while (child != NULL)
6963 	{
6964 	    get_framelayout(child, win_list, FALSE);
6965 	    child = child->fr_next;
6966 	}
6967     }
6968 }
6969 #endif
6970